e1000: dubious check for 100Mb speed.

[Colin Ian King <colin.king@xxxxxxxxxxxxx>]

Hi,

Static analysis with CoverityScan has detected an issue in
drivers/net/ethernet/intel/e1000/e1000_hw.c, function
e1000_config_mac_to_phy() as follows:

        case e1000_phy_8201:
                ret_val = e1000_read_phy_reg(hw, PHY_CTRL, &phy_data);
                if (ret_val)
                        return ret_val;

                if (phy_data & RTL_PHY_CTRL_FD)
                        ctrl |= E1000_CTRL_FD;
                else
                        ctrl &= ~E1000_CTRL_FD;

                if (phy_data & RTL_PHY_CTRL_SPD_100)
                        ctrl |= E1000_CTRL_SPD_100;
                else
                        ctrl |= E1000_CTRL_SPD_10;

                e1000_config_collision_dist(hw);
                break;

phy_data is a u16, however, RTL_PHY_CTRL_SPD_100 is 0x200000 and so the
bitwise and of phy_data & RTL_PHY_CTRL_SPD_100 is always zero, so ctrl
can never be set to the 100Mb speed.

Detected by CoverityScan, CID#140032 ("Operand's don't affect result").

Colin