scsi: ufs: Improve static type checking for the host controller state

Assign a name to the enumeration type for UFS host controller states and
remove the default clause from switch statements on this enumeration type
to make the compiler warn about unhandled enumeration labels.

Link: https://lore.kernel.org/r/20210722033439.26550-9-bvanassche@acm.org


Cc: Can Guo <cang@codeaurora.org>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Keoseong Park <keosung.park@samsung.com>
Reviewed-by: Daejun Park <daejun7.park@samsung.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>