qlcnic: make the array random_data static const, makes object smaller

Don't populate the array random_data on the stack but instead it
static const. Makes the object code smaller by 66 bytes.

Before:
   text    data     bss     dec     hex filename
  52895   10976       0   63871    f97f ../qlogic/qlcnic/qlcnic_ethtool.o

After:
   text    data     bss     dec     hex filename
  52701   11104       0   63805    f93d ../qlogic//qlcnic/qlcnic_ethtool.o

(gcc version 10.2.0)
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210801151659.146113-1-colin.king@canonical.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/qlogic/qlcnic/qlcnic_ethtool.c

@@ -1021,7 +1021,7 @@ static int qlcnic_irq_test(struct net_device *netdev)
 
 static void qlcnic_create_loopback_buff(unsigned char *data, u8 mac[])
 {
-	unsigned char random_data[] = {0xa8, 0x06, 0x45, 0x00};
+	static const unsigned char random_data[] = {0xa8, 0x06, 0x45, 0x00};
 
 	memset(data, 0x4e, QLCNIC_ILB_PKT_SIZE);