alpha: Fix duplicate <asm/thread_info.h> include

.. duplicated by merging the same fix twice, for details see commit
0d9df2515dbceb67d343c0f10fd3ff218380d524 ("Merge
git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-fixes")

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed