Add a temporary "fallback" header so architectures can run with the 4level
patgetables patch without modification. All architectures should be
converted to use the folding headers (include/asm-generic/pgtable-nop?d.h)
as soon as possible, and the fallback header removed.

Make all architectures include the fallback header, except i386, because that
architecture has earlier been converted to use pgtable-nopmd.h under the 3
level system, which is not compatible with the fallback header.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>