include/linux/smp.h:on_each_cpu(): switch back to a macro

include/linux/smp.h:on_each_cpu(): switch back to a macro

Commit f21afc25f9ed ("smp.h: Use local_irq_{save,restore}() in !SMP
version of on_each_cpu()") converted on_each_cpu() to a C function.

This required inclusion of irqflags.h, which broke ia64 and mn10300 (at
least) due to header ordering hell.

Switch on_each_cpu() back to a macro to fix this.

Reported-by: Geert Uytterhoeven <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Cc: David Daney <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: <[email protected]>	[3.10.x]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>