watchdog: gef_wdt: include fs.h

Add missing include "linux/fs.h".
This fixes compile failure.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Martyn Welch <martyn.welch@ge.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/gef_wdt.c b/drivers/watchdog/gef_wdt.c
index 9c21d19..f6bd6f1 100644
--- a/drivers/watchdog/gef_wdt.c
+++ b/drivers/watchdog/gef_wdt.c
@@ -30,6 +30,7 @@
 #include <linux/module.h>
 #include <linux/miscdevice.h>
 #include <linux/watchdog.h>
+#include <linux/fs.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/io.h>