ixgbe: add error checks when initializing the PHY

Ignoring errors when attempting to identify the PHY can lead to a crash.
Specifically in the case of FW controlled PHYs where the PHY read/write
operations are set to NULL.

Removed redundant comment.
Signed-off-by: NEmil Tantilov <emil.s.tantilov@intel.com>
Tested-by: NAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c

@@ -3192,6 +3192,9 @@ static s32 ixgbe_init_phy_ops_X550em(struct ixgbe_hw *hw)
 
 	/* Identify the PHY or SFP module */
 	ret_val = phy->ops.identify(hw);
+	if (ret_val == IXGBE_ERR_SFP_NOT_SUPPORTED ||
+	    ret_val == IXGBE_ERR_PHY_ADDR_INVALID)
+		return ret_val;
 
 	/* Setup function pointers based on detected hardware */
 	ixgbe_init_mac_link_ops_X550em(hw);
@@ -3394,9 +3397,10 @@ static s32 ixgbe_reset_hw_X550em(struct ixgbe_hw *hw)
 	ixgbe_clear_tx_pending(hw);
 
 	/* PHY ops must be identified and initialized prior to reset */
-
-	/* Identify PHY and related function pointers */
 	status = hw->phy.ops.init(hw);
+	if (status == IXGBE_ERR_SFP_NOT_SUPPORTED ||
+	    status == IXGBE_ERR_PHY_ADDR_INVALID)
+		return status;
 
 	/* start the external PHY */
 	if (hw->phy.type == ixgbe_phy_x550em_ext_t) {