scsi: ufs: sysfs: interconnect descriptor

This patch introduces a sysfs group entry for the UFS interconnect
descriptor parameters. The group adds "interconnect_descriptor" folder
under the UFS driver sysfs entry (/sys/bus/platform/drivers/ufshcd/*).
The parameters are shown as hexadecimal numbers. The full information
about the parameters could be found at UFS specifications 2.1.

Signed-off-by: Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>