phy: samsung: add enum for variants based on SoCs

phy: samsung: add enum for variants based on SoCs

The variant enum is used to uniquely identify which SoC the PHY block
belongs to. It is initially set in the match table, along with the
compatible string, it gets copied to driver data struct during probe.

SoC specific functions must only be called if the respective variant
enum is set. Add switch-case blocks wherever required.

Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>