scsi: message: fusion: Remove unused local variable 'vtarget'

Fix the following gcc warning:

drivers/message/fusion/mptsas.c:783:14: warning: variable ‘vtarget’ set
but not used [-Wunused-but-set-variable].

Link: https://lore.kernel.org/r/1618207146-96542-1-git-send-email-jiapeng.chong@linux.alibaba.com
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>