atl1c: add function atl1c_power_saving

This function is used for suspend of S1/S3/S4 and driver remove.
It sets MAC/PHY based on the WoL configuation to get lower power
consumption.
atl1c_phy_power_saving is renamed to atl1c_phy_to_ps_link, this
function is just make PHY enter a link/speed mode to eat less
power.
REG_MAC_CTRL register is refined as well.

Signed-off-by: xiong <xiong@qca.qualcomm.com>
Tested-by: Liu David <dwliu@qca.qualcomm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>