phy: cadence: Sierra: Add support to get SSC type from device tree

Add support to get SSC type from DT.

Signed-off-by: Swapnil Jakhade <sjakhade@cadence.com>
Reviewed-by: Aswath Govindraju <a-govindraju@ti.com>
Link: https://lore.kernel.org/r/20211223060137.9252-6-sjakhade@cadence.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>