Move a few cache functions into its own file and fix flush_icache_range() so
it can handle both kernel and user addresses correctly (assuming context is
set correctly).

Turn copy_to_user_page/copy_from_user_page into inline functions and add a
missing cache flush.
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>