uml: use get_free_pages to allocate kernel stacks

For some reason, I was using kmalloc instead of get_free_pages for kernel
stacks.

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>
1 file changed