[ACPI] remove "default m" from acpi/Kconfig

Andi Kleen suggested it was unconventional for us to "default m"
on ACPI modules -- even though they are expected to be deployed
as modules.  But as "default n" would likely result in some
users building nonsense kernels, we compromise to "default y".

Distros are expected to continue to use =m in their configs.
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/Kconfig

@@ -80,16 +80,16 @@ config ACPI_SLEEP_PROC_SLEEP
 config ACPI_AC
 	tristate "AC Adapter"
 	depends on X86
-	default m
+	default y
 	help
 	  This driver adds support for the AC Adapter object, which indicates
-	  whether a system is on AC, or not.  Typically, only mobile systems 
-	  have this object, since desktops are always on AC.
+	  whether a system is on AC, or not. If you have a system that can
+	  switch between A/C and battery, say Y.
 
 config ACPI_BATTERY
 	tristate "Battery"
 	depends on X86
-	default m
+	default y
 	help
 	  This driver adds support for battery information through
 	  /proc/acpi/battery. If you have a mobile system with a battery, 
@@ -97,18 +97,17 @@ config ACPI_BATTERY
 
 config ACPI_BUTTON
 	tristate "Button"
-	default m
+	default y
 	help
-	  This driver registers for events based on buttons, such as the
-	  power, sleep, and lid switch.  In the future, a daemon will read
-	  /proc/acpi/event and perform user-defined actions such as shutting
-	  down the system.  Until then, you can cat it, and see output when
-	  a button is pressed.
+	  This driver handles events on the power, sleep and lid buttons.
+	  A daemon reads /proc/acpi/event and perform user-defined actions
+	  such as shutting down the system.  This is necessary for
+	  software controlled poweroff.
 
 config ACPI_VIDEO
 	tristate "Video"
 	depends on X86
-	default m
+	default y
 	help
 	  This driver implement the ACPI Extensions For Display Adapters
 	  for integrated graphics devices on motherboard, as specified in
@@ -129,18 +128,19 @@ config ACPI_HOTKEY
 
 config ACPI_FAN
 	tristate "Fan"
-	default m
+	default y
 	help
 	  This driver adds support for ACPI fan devices, allowing user-mode 
 	  applications to perform basic fan control (on, off, status).
 
 config ACPI_PROCESSOR
 	tristate "Processor"
-	default m
+	default y
 	help
 	  This driver installs ACPI as the idle handler for Linux, and uses
 	  ACPI C2 and C3 processor states to save power, on systems that
-	  support it.
+	  support it.  It is required by several flavors of cpufreq
+	  Performance-state drivers.
 
 config ACPI_HOTPLUG_CPU
 	bool
@@ -151,7 +151,7 @@ config ACPI_HOTPLUG_CPU
 config ACPI_THERMAL
 	tristate "Thermal Zone"
 	depends on ACPI_PROCESSOR
-	default m
+	default y
 	help
 	  This driver adds support for ACPI thermal zones.  Most mobile and
 	  some desktop systems support ACPI thermal zones.  It is HIGHLY
@@ -167,7 +167,7 @@ config ACPI_NUMA
 config ACPI_ASUS
         tristate "ASUS/Medion Laptop Extras"
 	depends on X86
-	default m
+	default y
         ---help---
           This driver provides support for extra features of ACPI-compatible
           ASUS laptops. As some of Medion laptops are made by ASUS, it may also
@@ -196,7 +196,7 @@ config ACPI_ASUS
 config ACPI_IBM
 	tristate "IBM ThinkPad Laptop Extras"
 	depends on X86
-	default m
+	default y
 	---help---
 	  This is a Linux ACPI driver for the IBM ThinkPad laptops. It adds
 	  support for Fn-Fx key combinations, Bluetooth control, video
@@ -209,7 +209,7 @@ config ACPI_IBM
 config ACPI_TOSHIBA
 	tristate "Toshiba Laptop Extras"
 	depends on X86
-	default m
+	default y
 	---help---
 	  This driver adds support for access to certain system settings
 	  on "legacy free" Toshiba laptops.  These laptops can be recognized by
@@ -296,7 +296,7 @@ config X86_PM_TIMER
 	bool "Power Management Timer Support"
 	depends on X86
 	depends on !X86_64
-	default n
+	default y
 	help
 	  The Power Management Timer is available on all ACPI-capable,
 	  in most cases even if ACPI is unusable or blacklisted.