eth: Move IPv4/IPv6 multicast address bases to their own symbols

As these addresses can be useful outside of checking if an address
is a multicast address (for example in device drivers) make them
accessible to users of etherdevice.h to avoid code duplication.
Signed-off-by: Diogo Ivo <diogo.ivo@siemens.com>
Reviewed-by: MD Danish Anwar <danishanwar@ti.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

include/linux/etherdevice.h

@@ -71,6 +71,12 @@ static const u8 eth_reserved_addr_base[ETH_ALEN] __aligned(2) =
 { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
 #define eth_stp_addr eth_reserved_addr_base
 
+static const u8 eth_ipv4_mcast_addr_base[ETH_ALEN] __aligned(2) =
+{ 0x01, 0x00, 0x5e, 0x00, 0x00, 0x00 };
+
+static const u8 eth_ipv6_mcast_addr_base[ETH_ALEN] __aligned(2) =
+{ 0x33, 0x33, 0x00, 0x00, 0x00, 0x00 };
+
 /**
  * is_link_local_ether_addr - Determine if given Ethernet address is link-local
  * @addr: Pointer to a six-byte array containing the Ethernet address
@@ -430,18 +436,16 @@ static inline bool ether_addr_equal_masked(const u8 *addr1, const u8 *addr2,
 
 static inline bool ether_addr_is_ipv4_mcast(const u8 *addr)
 {
-	u8 base[ETH_ALEN] = { 0x01, 0x00, 0x5e, 0x00, 0x00, 0x00 };
 	u8 mask[ETH_ALEN] = { 0xff, 0xff, 0xff, 0x80, 0x00, 0x00 };
 
-	return ether_addr_equal_masked(addr, base, mask);
+	return ether_addr_equal_masked(addr, eth_ipv4_mcast_addr_base, mask);
 }
 
 static inline bool ether_addr_is_ipv6_mcast(const u8 *addr)
 {
-	u8 base[ETH_ALEN] = { 0x33, 0x33, 0x00, 0x00, 0x00, 0x00 };
 	u8 mask[ETH_ALEN] = { 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 };
 
-	return ether_addr_equal_masked(addr, base, mask);
+	return ether_addr_equal_masked(addr, eth_ipv6_mcast_addr_base, mask);
 }
 
 static inline bool ether_addr_is_ip_mcast(const u8 *addr)