irqflags.h changes

大约在2.6.18左右

Currently, linux/irqflags.h defines local_irq_enable() and friends
through raw_* counterparts.

Sometimes it defines raw_* counterparts through local_irq_enable() and
friends.

I'm going to end this subtle joke and make on all archs:

local_irq_enable() via raw_local_irq_enable()
local_irq_disable() via raw_local_irq_disable()
local_irq_save() via raw_local_irq_save()
local_irq_restore() via raw_local_irq_restore() + stuff
local_save_flags() via raw_local_save_flags()
irqs_disabled() via raw_irqs_disabled_flags() + stuff

linux/irqflags.h will include asm/irqflags.h unconditionally.
Arches that don't have asm/irqflags.h will get it through extraction
from asm/system.h or whatever.

Users will just include

Irq tracing will remain the same (it's nop depending on config option,
after all).