security/min_addr.c: make init_mmap_min_addr() static

init_mmap_min_addr() is a pure_initcall and should be static.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Morris <jmorris@namei.org>