phy: cadence: Sierra: Add single link SGMII register configuration

Add single link SGMII register configuration for no SSC for
cdns,sierra-phy-t0 compatibility string.
The configuration is based on Sierra Programmer's Guide and
validated in Cisco CrayAR SoC.

Co-developed-by: Bartosz Wawrzyniak <bwawrzyn@cisco.com>
Signed-off-by: Bartosz Wawrzyniak <bwawrzyn@cisco.com>
Signed-off-by: Marcin Wierzbicki <mawierzb@cisco.com>
Link: https://lore.kernel.org/r/20230626105533.2999966-1-mawierzb@cisco.com


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