fs/direct-io.c: include fs/internal.h for missing prototype

Include fs/internal.h to address the following 'sparse' warning:

    fs/direct-io.c:591:5: warning: symbol 'sb_init_dio_done_wq' was not declared. Should it be static?

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Eric Biggers <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Cc: Alexander Viro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: ebiggers

fs/direct-io.c

@@ -39,6 +39,8 @@
 #include <linux/atomic.h>
 #include <linux/prefetch.h>
 
+#include "internal.h"
+
 /*
  * How many user pages to map in one call to get_user_pages().  This determines
  * the size of a structure in the slab cache