Export tiny shmem_file_setup for DRM-GEM

We're trying to keep the !CONFIG_SHMEM tiny-shmem.c (using ramfs without
swap) in synch with CONFIG_SHMEM shmem.c (and mpm is preparing patches
to combine them).  I was glad to see EXPORT_SYMBOL_GPL(shmem_file_setup)
go into shmem.c, but why not support DRM-GEM when !CONFIG_SHMEM too?
But caution says still depend on MMU, since !CONFIG_MMU is.. different.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: Matt Mackall <mpm@selenic.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/tiny-shmem.c b/mm/tiny-shmem.c
index 8d7a27a..3e67d57 100644
--- a/mm/tiny-shmem.c
+++ b/mm/tiny-shmem.c
@@ -95,6 +95,7 @@
 put_memory:
 	return ERR_PTR(error);
 }
+EXPORT_SYMBOL_GPL(shmem_file_setup);
 
 /**
  * shmem_zero_setup - setup a shared anonymous mapping