bnxt_en: Skip PHY loopback ethtool selftest if unsupported by FW

Skip PHY loopback selftest if firmware advertises that it is unsupported
in the HWRM_PORT_PHY_QCAPS call.  Only show PHY loopback test result to
be 0 if the test has run and passes.  Do the same for external loopback
to be consistent.

Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20241217182620.2454075-4-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Michael Chan

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

@@ -4914,20 +4914,26 @@ static void bnxt_self_test(struct net_device *dev, struct ethtool_test *etest,
 			buf[BNXT_MACLPBK_TEST_IDX] = 0;
 
 		bnxt_hwrm_mac_loopback(bp, false);
+		buf[BNXT_PHYLPBK_TEST_IDX] = 1;
+		if (bp->phy_flags & BNXT_PHY_FL_NO_PHY_LPBK)
+			goto skip_phy_loopback;
+
 		bnxt_hwrm_phy_loopback(bp, true, false);
 		msleep(1000);
-		if (bnxt_run_loopback(bp)) {
-			buf[BNXT_PHYLPBK_TEST_IDX] = 1;
+		if (bnxt_run_loopback(bp))
 			etest->flags |= ETH_TEST_FL_FAILED;
-		}
+		else
+			buf[BNXT_PHYLPBK_TEST_IDX] = 0;
+skip_phy_loopback:
+		buf[BNXT_EXTLPBK_TEST_IDX] = 1;
 		if (do_ext_lpbk) {
 			etest->flags |= ETH_TEST_FL_EXTERNAL_LB_DONE;
 			bnxt_hwrm_phy_loopback(bp, true, true);
 			msleep(1000);
-			if (bnxt_run_loopback(bp)) {
-				buf[BNXT_EXTLPBK_TEST_IDX] = 1;
+			if (bnxt_run_loopback(bp))
 				etest->flags |= ETH_TEST_FL_FAILED;
-			}
+			else
+				buf[BNXT_EXTLPBK_TEST_IDX] = 0;
 		}
 		bnxt_hwrm_phy_loopback(bp, false, false);
 		bnxt_half_close_nic(bp);