asm/system.h: clean asm/system.h from docs

Clean asm/system.h from docs as nothing should refer to that header anymore.
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/DocBook/kernel-hacking.tmpl

@@ -671,7 +671,7 @@ printk(KERN_INFO "my ip: %pI4\n", &ipaddress);
 
   <sect1 id="routines-local-irqs">
    <title><function>local_irq_save()</function>/<function>local_irq_restore()</function>
-    <filename class="headerfile">include/asm/system.h</filename>
+    <filename class="headerfile">include/linux/irqflags.h</filename>
    </title>
 
    <para>

Documentation/irqflags-tracing.txt

@@ -22,13 +22,6 @@ rather straightforward and risk-free manner.
 Architectures that want to support this need to do a couple of
 code-organizational changes first:
 
-- move their irq-flags manipulation code from their asm/system.h header
-  to asm/irqflags.h
-
-- rename local_irq_disable()/etc to raw_local_irq_disable()/etc. so that
-  the linux/irqflags.h code can inject callbacks and can construct the
-  real local_irq_disable()/etc APIs.
-
 - add and enable TRACE_IRQFLAGS_SUPPORT in their arch level Kconfig file
 
 and then a couple of functional changes are needed as well to implement

Documentation/scheduler/sched-arch.txt

@@ -8,7 +8,7 @@ Context switch
 By default, the switch_to arch function is called with the runqueue
 locked. This is usually not a problem unless switch_to may need to
 take the runqueue lock. This is usually due to a wake up operation in
-the context switch. See arch/ia64/include/asm/system.h for an example.
+the context switch. See arch/ia64/include/asm/switch_to.h for an example.
 
 To request the scheduler call switch_to with the runqueue unlocked,
 you must `#define __ARCH_WANT_UNLOCKED_CTXSW` in a header file