[PATCH] arch/i386/mm/init.c: small cleanups

This patch contains the following cleanups:
- make a needlessly global function static
- every file should include the headers containing the prototypes for
  it's global functions

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>