gfs2: setattr_chown: Add missing initialization

Add a missing initialization of variable ap in setattr_chown().
Without, chown() may be able to bypass quotas.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/inode.c

@@ -1927,7 +1927,7 @@ static int setattr_chown(struct inode *inode, struct iattr *attr)
 	kuid_t ouid, nuid;
 	kgid_t ogid, ngid;
 	int error;
-	struct gfs2_alloc_parms ap;
+	struct gfs2_alloc_parms ap = {};
 
 	ouid = inode->i_uid;
 	ogid = inode->i_gid;