scsi: pmcraid: Remove set but not used 'res'

scsi: pmcraid: Remove set but not used 'res'

This addresses the following gcc warning with "make W=1":

 drivers/scsi/pmcraid.c: In function ‘pmcraid_abort_cmd’:
 drivers/scsi/pmcraid.c:2863:33: warning: variable ‘res’ set but not
 used [-Wunused-but-set-variable]
   struct pmcraid_resource_entry *res;
                                    ^

Link: https://lore.kernel.org/r/20200909082627.101984-2-yebin10@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>