scsi: ufs-cdns: Add support for UFSHCI with M31 PHY

This patch adds an additional PHY initialization, required for M31 PHY when
used with Cadence UFS HC.  A new compatible string has been added for this
purpose.

[mkp: nuke superfluous status return]

Signed-off-by: Jan Kotas <jank@cadence.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>