scsi: qla4xxx: Remove set but unused variable 'func_number'

scsi: qla4xxx: Remove set but unused variable 'func_number'

Fixes the following W=1 kernel build warning(s):

 drivers/scsi/qla4xxx/ql4_init.c: In function ‘ql4xxx_set_mac_number’:
 drivers/scsi/qla4xxx/ql4_init.c:17:10: warning: variable ‘func_number’ set but not used [-Wunused-but-set-variable]

Link: https://lore.kernel.org/r/20200721164148.2617584-13-lee.jones@linaro.org
Cc: QLogic-Storage-Upstream@qlogic.com
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>