cxgb4vf: Use defined Mailbox Timeout

VF Driver should use mailbox command timeout specified in t4fw_interface.h
rather than hard-coded value of 500ms.
Signed-off-by: NCasey Leedom <leedom@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/cxgb4vf/t4vf_hw.c

@@ -171,7 +171,7 @@ int t4vf_wr_mbox_core(struct adapter *adapter, const void *cmd, int size,
 	delay_idx = 0;
 	ms = delay[0];
 
-	for (i = 0; i < 500; i += ms) {
+	for (i = 0; i < FW_CMD_MAX_TIMEOUT; i += ms) {
 		if (sleep_ok) {
 			ms = delay[delay_idx];
 			if (delay_idx < ARRAY_SIZE(delay) - 1)