drivers: ata: Move sata port phy oob settings to device-tree

drivers: ata: Move sata port phy oob settings to device-tree

In SATA Speed negotiation happens with  OOB(Out of Band) signals. These OOB
signal timing values are configured through vendor specific registers in the
SATA controller. These OOB timings depends on the generator and detector clock
frequency, which varies from board to board (ex: ep108 and zc1751 has different
clock frequencies).
To avoid maintaing these OOB settings in the driver, it is better to move these
settings to the device-tree node and read from the device-tree.

This patch does the same.

Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>