Blackfin arch: after removing fs.h from mm.h, fix the broken on Blackfin arch

Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/blackfin/kernel/init_task.c b/arch/blackfin/kernel/init_task.c
index b45188f..673c860 100644
--- a/arch/blackfin/kernel/init_task.c
+++ b/arch/blackfin/kernel/init_task.c
@@ -31,6 +31,7 @@
 #include <linux/module.h>
 #include <linux/init_task.h>
 #include <linux/mqueue.h>
+#include <linux/fs.h>
 
 static struct fs_struct init_fs = INIT_FS;
 static struct files_struct init_files = INIT_FILES;