nfc: st-nci: Remove pr_err in rcv_queue when ndlc header is unknown

spi phy needs to use ndlc_recv at every spi transaction causing
"unknown packet control byte" error message each time the header
is 00. Make this silent.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/nfc/st-nci/ndlc.c

@@ -194,7 +194,6 @@ static void llt_ndlc_rcv_queue(struct llt_ndlc *ndlc)
 					  msecs_to_jiffies(NDLC_TIMER_T1_WAIT));
 				break;
 			default:
-				pr_err("UNKNOWN Packet Control Byte=%d\n", pcb);
 				kfree_skb(skb);
 				break;
 			}