scsi: ufs: ufs-exynos: Add UFS host support for Exynos SoCs

This patch introduces Exynos UFS host controller driver which mainly
handles vendor-specific operations including link startup, power mode
change and hibernation/unhibernation.

[robot: drivers/scsi/ufs/ufs-exynos.c:931:8-10:
 WARNING: possible condition with no effect (if == else)
]

Link: https://lore.kernel.org/r/20200528011658.71590-10-alim.akhtar@samsung.com


Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Tested-by: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
Reviewed-by: Kiwoong Kim <kwmad.kim@samsung.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Seungwon Jeon <essuuj@gmail.com>
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>