MLK-15341 mx6qpsabresd: add PHY AR8031 hw reset

MLK-15341 mx6qpsabresd: add PHY AR8031 hw reset

Currently mx6qpsabresd board file only add PHY AR8031 gpio reset
in non-DM driver, then net DM driver PHY cannot work after stress
reboot test. So also add gpio reset for DM driver.

RGMII and PHY work at VDDIO 1.8V has better timing and to align
the IO voltage with kernel, also set the IO voltage to 1.8V.

Since i.MX6QP tx_clk can loop from SOC internal, no need to set
PHY output 125Mhz clock that can save power.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>