ixgbe: Clarify the values of the returning status

Converting s32 functions to regular int in the previous patch of the series
caused triggering smatch warnings about missing error code.

New smatch warnings:
drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c:2884 ixgbe_get_lcd_t_x550em() warn: missing error code? 'status'
drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c:3130 ixgbe_enter_lplu_t_x550em() warn: missing error code? 'status'

Old smatch warnings:
drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c:2890 ixgbe_get_lcd_t_x550em() warn: missing error code? 'status'

Fix it by clearly stating returning error code as 0.
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202401041701.6QKTsZmx-lkp@intel.com/Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Jedrzej Jagielski <jedrzej.jagielski@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

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

@@ -2884,17 +2884,17 @@ static int ixgbe_get_lcd_t_x550em(struct ixgbe_hw *hw,
 	/* If link partner advertised 1G, return 1G */
 	if (an_lp_status & IXGBE_AUTO_NEG_LP_1000BASE_CAP) {
 		*lcd_speed = IXGBE_LINK_SPEED_1GB_FULL;
-		return status;
+		return 0;
 	}
 
 	/* If 10G disabled for LPLU via NVM D10GMP, then return no valid LCD */
 	if ((hw->bus.lan_id && (word & NVM_INIT_CTRL_3_D10GMP_PORT1)) ||
 	    (word & NVM_INIT_CTRL_3_D10GMP_PORT0))
-		return status;
+		return 0;
 
 	/* Link partner not capable of lower speeds, return 10G */
 	*lcd_speed = IXGBE_LINK_SPEED_10GB_FULL;
-	return status;
+	return 0;
 }
 
 /**
@@ -3130,7 +3130,7 @@ static int ixgbe_enter_lplu_t_x550em(struct ixgbe_hw *hw)
 	     (lcd_speed == IXGBE_LINK_SPEED_1GB_FULL)) ||
 	    ((speed == IXGBE_MDIO_AUTO_NEG_VENDOR_STATUS_10GB) &&
 	     (lcd_speed == IXGBE_LINK_SPEED_10GB_FULL)))
-		return status;
+		return 0;
 
 	/* Clear AN completed indication */
 	status = hw->phy.ops.read_reg(hw, IXGBE_MDIO_AUTO_NEG_VENDOR_TX_ALARM,