can: sun4i_can: continue to use likely() to check skb

Throughout the sun4i_can_err() function, the likely() macro is used to
check the skb buffer, except in one instance. This patch makes the code
consistent by using the macro in that case as well.

Signed-off-by: Dario Binacchi <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Marc Kleine-Budde <[e-mail]>

drivers/net/can/sun4i_can.c

···
 		else
 			state = CAN_STATE_ERROR_ACTIVE;
 	}
-	if (skb && state != CAN_STATE_BUS_OFF) {
+	if (likely(skb) && state != CAN_STATE_BUS_OFF) {
 		cf->can_id |= CAN_ERR_CNT;
 		cf->data[6] = txerr;
 		cf->data[7] = rxerr;