scsi: 3w-xxx: Remove redundant initialization of variable retval

The variable retval is being initialized with a value that is never read,
it is being updated immediately afterwards. The assignment is redundant and
can be removed.

Link: https://lore.kernel.org/r/20211013182834.137410-1-colin.king@canonical.com


Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Addresses-Coverity: ("Unused value")