[PATCH] net: ethernet: mtk_eth_soc: fix error checking in mtk_mac_config()

[trix@redhat.com]

From: Tom Rix <trix@redhat.com>

Clang static analysis reports this problem
mtk_eth_soc.c:394:7: warning: Branch condition evaluates
  to a garbage value
                if (err)
                    ^~~

err is not initialized and only conditionally set.
Check err consistently with the rest of mtk_mac_config(),
after even possible setting.

Fixes: 7e538372694b ("net: ethernet: mediatek: Re-add support SGMII")
Signed-off-by: Tom Rix <trix@redhat.com>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index b67b4323cff08..a27e548488584 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -385,14 +385,16 @@ static void mtk_mac_config(struct phylink_config *config, unsigned int mode,
 		       0 : mac->id;
 
 		/* Setup SGMIISYS with the determined property */
-		if (state->interface != PHY_INTERFACE_MODE_SGMII)
+		if (state->interface != PHY_INTERFACE_MODE_SGMII) {
 			err = mtk_sgmii_setup_mode_force(eth->sgmii, sid,
 							 state);
-		else if (phylink_autoneg_inband(mode))
+			if (err)
+				goto init_err;
+		} else if (phylink_autoneg_inband(mode)) {
 			err = mtk_sgmii_setup_mode_an(eth->sgmii, sid);
-
-		if (err)
-			goto init_err;
+			if (err)
+				goto init_err;
+		}
 
 		regmap_update_bits(eth->ethsys, ETHSYS_SYSCFG0,
 				   SYSCFG0_SGMII_MASK, val);
-- 
2.26.3