scsi: qla4xxx: Remove unused 'count' variable

clang with W=1 reports:

drivers/scsi/qla4xxx/ql4_isr.c:475:11: error: variable
  'count' set but not used [-Werror,-Wunused-but-set-variable]
        uint32_t count = 0;
                 ^
This variable is not used so remove it.

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20230331175757.1860780-1-trix@redhat.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>