phy: cadence-torrent: Add single link PCIe support

Add single link PCIe register sequences in Torrent PHY driver.
Also, add support for getting SSC type from DT.
Signed-off-by: Swapnil Jakhade <sjakhade@cadence.com>
Link: https://lore.kernel.org/r/1600327846-9733-2-git-send-email-sjakhade@cadence.comSigned-off-by: Vinod Koul <vkoul@kernel.org>