net: aquantia: make function aq_fw2x_get_mac_permanent static

The function aq_fw2x_get_mac_permanent is local to the source and does
not need to be in global scope, so make it static.

Cleans up sparse warning:
warning: symbol 'aq_fw2x_get_mac_permanent' was not declared. Should it
be static?

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_utils_fw2x.c

@@ -107,7 +107,7 @@ static int aq_fw2x_update_link_status(struct aq_hw_s *self)
 	return 0;
 }
 
-int aq_fw2x_get_mac_permanent(struct aq_hw_s *self, u8 *mac)
+static int aq_fw2x_get_mac_permanent(struct aq_hw_s *self, u8 *mac)
 {
 	int err = 0;
 	u32 h = 0U;