[GFS2] build fix

fs/gfs2/glock.c:2198: error: 'THIS_MODULE' undeclared here (not in a function)

Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/gfs2/glock.c

@@ -20,6 +20,7 @@
 #include <linux/list.h>
 #include <linux/lm_interface.h>
 #include <linux/wait.h>
+#include <linux/module.h>
 #include <linux/rwsem.h>
 #include <asm/uaccess.h>