scsi: mptscsih: Remove set but not used 'timeleft'

scsi: mptscsih: Remove set but not used 'timeleft'

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

drivers/message/fusion/mptscsih.c: In function ‘mptscsih_IssueTaskMgmt’:
drivers/message/fusion/mptscsih.c:1519:17: warning: variable ‘timeleft’
set but not used [-Wunused-but-set-variable]
 1519 |  unsigned long  timeleft;
      |                 ^~~~~~~~

Link: https://lore.kernel.org/r/20200827125925.428357-1-yanaijie@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>