phy: cadence-torrent: Add 19.2 MHz reference clock support

Add configuration functions for 19.2 MHz refclock support.
Add register configurations for SSC support.

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>