uml: fix inlines

"extern inline" will have different semantics with gcc 4.3.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>