[PATCH] mm/migrate.c: don't export a static function

EXPORT_SYMBOL'ing of a static function is not a good idea.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>