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>

drivers/scsi/qla4xxx/ql4_init.c

@@ -14,7 +14,6 @@
 static void ql4xxx_set_mac_number(struct scsi_qla_host *ha)
 {
 	uint32_t value;
-	uint8_t func_number;
 	unsigned long flags;
 
 	/* Get the function number */
@@ -22,7 +21,6 @@ static void ql4xxx_set_mac_number(struct scsi_qla_host *ha)
 	value = readw(&ha->reg->ctrl_status);
 	spin_unlock_irqrestore(&ha->hardware_lock, flags);
 
-	func_number = (uint8_t) ((value >> 4) & 0x30);
 	switch (value & ISP_CONTROL_FN_MASK) {
 	case ISP_CONTROL_FN0_SCSI:
 		ha->mac_index = 1;