GFS2: Delete an unnecessary check before the function call "iput"

The iput() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

fs/gfs2/ops_fstype.c

@@ -910,8 +910,7 @@ static int init_per_node(struct gfs2_sbd *sdp, int undo)
 fail_ut_i:
 	iput(sdp->sd_sc_inode);
 fail:
-	if (pn)
-		iput(pn);
+	iput(pn);
 	return error;
 }