userfaultfd: shmem: add tlbflush.h header for microblaze

It resolves this build error:

All errors (new ones prefixed by >>):

   mm/shmem.c: In function 'shmem_mcopy_atomic_pte':
   >> mm/shmem.c:2228:2: error: implicit declaration of function 'update_mmu_cache' [-Werror=implicit-function-declaration]
        update_mmu_cache(dst_vma, dst_addr, dst_pte);

microblaze may have to be also updated to define it in asm/pgtable.h
like the other archs, then this header inclusion can be removed.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Andrea Arcangeli <[email protected]>
Cc: "Dr. David Alan Gilbert" <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Michael Rapoport <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

mm/shmem.c

@@ -34,6 +34,8 @@
 #include <linux/uio.h>
 #include <linux/khugepaged.h>
 
+#include <asm/tlbflush.h> /* for arch/microblaze update_mmu_cache() */
+
 static struct vfsmount *shm_mnt;
 
 #ifdef CONFIG_SHMEM