scsi: ufs: Factor out ufshcd_read_desc_param

Since in UFS 2.1 specification some of the descriptor lengths differs
from 2.0 specification and some devices, which are reporting spec
version 2.0 have different descriptor lengths we can not rely on
hardcoded values taken from 2.0 specification. This patch introduces
reading these lengths per each device from descriptor headers at probe
time to ensure their correctness.

Signed-off-by: Michal' Potomski <michalx.potomski@intel.com>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>