Add CONFIG_X86_32 for i386.  This allows selecting options that only apply
to 32-bit systems.

(X86 && !X86_64) becomes X86_32
(X86 ||  X86_64) becomes X86
Signed-off-by: Brian Gerst <bgerst@didntduck.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>