scsi: ufs: Fix memory corruption by ufshcd_read_desc_param()

If param_offset > buff_len then the memcpy() statement in
ufshcd_read_desc_param() corrupts memory since it copies 256 + buff_len -
param_offset bytes into a buffer with size buff_len.  Since param_offset <
256 this results in writing past the bound of the output buffer.

Link: https://lore.kernel.org/r/20210722033439.26550-2-bvanassche@acm.org


Fixes: cbe193f6 ("scsi: ufs: Fix potential NULL pointer access during memcpy")
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Daejun Park <daejun7.park@samsung.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>