can: remove obsolete assignment for CAN protocol error type

The assignment 'cf->data[2] |= CAN_ERR_PROT_UNSPEC' used at CAN error message
creation time is obsolete as CAN_ERR_PROT_UNSPEC is zero and cf->data[2] is
initialized with zero in alloc_can_err_skb() anyway.

So we could either assign 'cf->data[2] = CAN_ERR_PROT_UNSPEC' correctly or we
can remove the obsolete OR operation entirely.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
index 4c57ddf..51670b3 100644
--- a/drivers/net/can/xilinx_can.c
+++ b/drivers/net/can/xilinx_can.c
@@ -608,10 +608,8 @@
 
 	/* Check for error interrupt */
 	if (isr & XCAN_IXR_ERROR_MASK) {
-		if (skb) {
+		if (skb)
 			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
-			cf->data[2] |= CAN_ERR_PROT_UNSPEC;
-		}
 
 		/* Check for Ack error interrupt */
 		if (err_status & XCAN_ESR_ACKER_MASK) {