[PATCH] Catch notification of memory add event of ACPI via container driver. (avoid redundant call add_memory)

When acpi_memory_device_init() is called at boottime to register struct
memory acpi_memory_device, acpi_bus_add() are called via
acpi_driver_attach().

But it also calls ops->start() function.  It is called even if the memory
blocks are initialized at early boottime.  In this case add_memory() return
-EEXIST, and the memory blocks becomes INVALID state even if it is normal.

This is patch to avoid calling add_memory() for already available memory.

[akpm@osdl.org: coding cleanups]
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: "Brown, Len" <len.brown@intel.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>