glib-aux: drop ethernet fields from NMIPAddr union

It's not really used anyway.

The idea was, that the ethernet MAC address would fit from the size, and
we might at a few places use that for convenience. But it's more
confusing. Also, because there is already NMEtherAddr and `struct
ether_addr`.

src/libnm-glib-aux/nm-inet-utils.h

@@ -9,13 +9,6 @@ typedef struct _NMIPAddr {
         in_addr_t       addr4;
         struct in_addr  addr4_struct;
         struct in6_addr addr6;
-
-        /* NMIPAddr is really a union for IP addresses.
-         * However, as ethernet addresses fit in here nicely, use
-         * it also for an ethernet MAC address. */
-        guint8      ether_addr_octet[6 /*ETH_ALEN*/];
-        NMEtherAddr ether_addr;
-
         guint8          array[sizeof(struct in6_addr)];
     };
 } NMIPAddr;