initcalls: Add early_initcall() for modules

Complete the early_initcall() API by making it available in modules
too. To be used by the EDAC/MCE code.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
LKML-Reference: <20091002132321.GC28682@aftab>
Signed-off-by: Ingo Molnar <mingo@elte.hu>