scsi: ufs: set default UFS power management level

UFS device and link can be put in multiple different low power modes hence
UFS driver supports multiple different low power modes.
This change sets the default UFS power management level which should put
the link hibernate state and device in sleep state. This default power
management level gives good  power savings with relatively less enter/exit
latencies.

Reviewed-by: Yaniv Gardi <ygardi@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>