scsi: ufs: Use an SPDX license identifier in the Kconfig file

As requested in Documentation/process/license-rules.rst, use an SPDX
license identifier.

Link: https://lore.kernel.org/r/20220419225811.4127248-18-bvanassche@acm.org


Tested-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>