Add a driver for the Motorcomm yt8511 phy that will be used in the production Pine64 rk3566-quartz64 development board. It supports gigabit transfer speeds, rgmii, and 125mhz clk output. Signed-off-by: Peter Geis <pgwipeout@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: David Wu <david.wu@rock-chips.com> (cherry-pick from commit 48e8c6f1612b3d2dccaea2285231def830cc5b8e) Change-Id: If0af67cda0ad607e4a31f126804547e9d8b3df50