scsi: ufs: ufshcd_get_max_icc_level fix endianity handling

Reading big endian value from a buffer requires explicit cast.
Fix sparse warning:
drivers/scsi/ufs/ufshcd.c:4825:24: warning: cast to restricted __be16

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>