at86rf230: fix simple_return.cocci warnings

drivers/net/ieee802154/at86rf230.c:1365:1-3: WARNING: end returns can be simpified

 Simplify a trivial if-return sequence.  Possibly combine with a
 preceding function call.
Generated by: scripts/coccinelle/misc/simple_return.cocci
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Acked-by: NAlexander Aring <alex.aring@gmail.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

drivers/net/ieee802154/at86rf230.c

@@ -1362,11 +1362,7 @@ static int at86rf230_hw_init(struct at86rf230_local *lp)
 	 * sets this bit and I don't know why. We set this always force
 	 * to zero while probing.
 	 */
-	rc = at86rf230_write_subreg(lp, SR_SLOTTED_OPERATION, 0);
-	if (rc)
-		return rc;
-
-	return 0;
+	return at86rf230_write_subreg(lp, SR_SLOTTED_OPERATION, 0);
 }
 
 static struct at86rf230_platform_data *