For UFS 3.1, the normal unit descriptor is 10 bytes larger than the RPMB
unit. However, both descriptors share the same desc_idn, to cover both unit
descriptors with one length, we choose the normal unit descriptor length by
desc_index.

Link: https://lore.kernel.org/r/20200603091959.27618-6-huobean@gmail.comReviewed-by: NAvri Altman <avri.altman@wdc.com>
Signed-off-by: NBean Huo <beanhuo@micron.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>