phy: cadence-torrent: Add support for subnode bindings

Implement single link subnode support to the phy driver.
Add reset support including PHY reset and individual lane reset.
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>