Add support for PHY configuration APIs. These will mainly reconfigure link rate, number of lanes, voltage swing and pre-emphasis values. Signed-off-by: Swapnil Jakhade <sjakhade@cadence.com> Signed-off-by: Yuti Amonkar <yamonkar@cadence.com> Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>