net: atlantic: fix PTP on AQC10X

This patch fixes PTP on AQC10X.
PTP support on AQC10X requires FW involvement and FW configures the
TPS data arb mode itself.
So we must make sure driver doesn't touch TPS data arb mode on AQC10x
if PTP is enabled. Otherwise, there are no timestamps even though
packets are flowing.

Fixes: 2deac71a ("net: atlantic: QoS implementation: min_rate")
Signed-off-by: Egor Pomozov <epomozov@marvell.com>
Signed-off-by: Mark Starovoytov <mstarovoitov@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c

@@ -373,8 +373,13 @@ static int hw_atl_b0_hw_init_tx_tc_rate_limit(struct aq_hw_s *self)
 
 	/* WSP, if min_rate is set for at least one TC.
 	 * RR otherwise.
+	 *
+	 * NB! MAC FW sets arb mode itself if PTP is enabled. We shouldn't
+	 * overwrite it here in that case.
 	 */
+	if (!nic_cfg->is_ptp)
 		hw_atl_tps_tx_pkt_shed_data_arb_mode_set(self, min_rate_msk ? 1U : 0U);
+
 	/* Data TC Arbiter takes precedence over Descriptor TC Arbiter,
 	 * leave Descriptor TC Arbiter as RR.
 	 */