scsi: ufs: ufs-exynos: Factor out priv data init

To leverage the initialization code for the other variant of the exynos-ufs
driver, factor out the assignment part.

Link: https://lore.kernel.org/r/20211018124216.153072-10-chanho61.park@samsung.com


Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Kiwoong Kim <kwmad.kim@samsung.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>