The init_fs symbol is defined in <linux/init_task.h> but was
not included in fs/fs_struct.c so fix by adding the include.

Fixes the following sparse warning:
fs/fs_struct.c:150:18: warning: symbol 'init_fs' was not declared. Should it be static?

Fixes: 3e93cd671813e ("Take fs_struct handling to new file")
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
---
 fs/fs_struct.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/fs_struct.c b/fs/fs_struct.c
index b8c46c5a38a0..394875d06fd6 100644
--- a/fs/fs_struct.c
+++ b/fs/fs_struct.c
@@ -6,6 +6,7 @@
 #include <linux/path.h>
 #include <linux/slab.h>
 #include <linux/fs_struct.h>
+#include <linux/init_task.h>
 #include "internal.h"
 
 /*
-- 
2.37.2.352.g3c44437643