remove linux/hardirq.h from asm-generic/local.h

While looking at reducing the amount of architecture namespace pollution
in the generic kernel, I found that asm/irq.h is included in the vast
majority of compilations on ARM (around 650 files.)

Since asm/irq.h includes a sub-architecture include file on ARM, this
causes a negative impact on the ccache's ability to re-use the build
results from other sub-architectures, so we have a desire to reduce the
dependencies on asm/irq.h.

It turns out that a major cause of this is the needless include of
linux/hardirq.h into asm-generic/local.h.  The patch below removes this
include, resulting in some 250 to 300 files (around half) of the kernel
then omitting asm/irq.h.

My test builds still succeed, provided two ARM files are fixed
(arch/arm/kernel/traps.c and arch/arm/mm/fault.c) - so there may be
negative impacts for this on other architectures.

Note that x86 does not include asm/irq.h nor linux/hardirq.h in its
asm/local.h, so this patch can be viewed as bringing the generic version
into line with the x86 version.

[[email protected]: add #include <linux/irqflags.h> to acpi/processor_idle.c]
[[email protected]: fix sparc64]
Signed-off-by: Russell King <[email protected]>
Signed-off-by: KOSAKI Motohiro <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

drivers/acpi/processor_idle.c

@@ -41,6 +41,7 @@
 #include <linux/pm_qos_params.h>
 #include <linux/clockchips.h>
 #include <linux/cpuidle.h>
+#include <linux/irqflags.h>
 
 /*
  * Include the apic definitions for x86 to have the APIC timer related defines