scsi: ufs: optimize the sending of REQUEST_SENSE to device W-LU

UFS device W-LU (Well known Logical Unit)'s UNIT ATTENTION condition will
not be cleared until explict REQUEST_SENSE scsi command is issued to it
once and then after UNIT ATTENTION condition should remain cleared until
device reset or power-on. Current implementation of UFS driver may send
the REQUEST_SEND command multiple time which is really not needed. This
change would send the REQUEST_SENSE only once after the device reset or
power-on.

Change-Id: I20292e12cbbeded18befffe73abbf2e99ef21ba1
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>