net: netcp: fix check of requested timestamping filter

The driver doesn't support timestamping of all received packets and
should return error when trying to enable the HWTSTAMP_FILTER_ALL
filter.

Cc: WingMan Kwok <w-kwok2@ti.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/ti/netcp_ethss.c

@@ -2651,7 +2651,6 @@ static int gbe_hwtstamp_set(struct gbe_intf *gbe_intf, struct ifreq *ifr)
 	case HWTSTAMP_FILTER_NONE:
 		cpts_rx_enable(cpts, 0);
 		break;
-	case HWTSTAMP_FILTER_ALL:
 	case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
 	case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
 	case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ: