MIPS: BCM63XX: provide a MAC address for BCM3368 chips

The BCM3368 SoC uses a NVRAM format which is not compatible with the one
used by CFE, provide a default MAC address which is suitable for use and
which is the default one also being used by the bootloader on these
chips.
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: cernekee@gmail.com
Cc: jogo@openwrt.org
Patchwork: https://patchwork.linux-mips.org/patch/5498/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/bcm63xx/nvram.c

@@ -42,6 +42,7 @@ void __init bcm63xx_nvram_init(void *addr)
 {
 	unsigned int check_len;
 	u32 crc, expected_crc;
+	u8 hcs_mac_addr[ETH_ALEN] = { 0x00, 0x10, 0x18, 0xff, 0xff, 0xff };
 
 	/* extract nvram data */
 	memcpy(&nvram, addr, sizeof(nvram));
@@ -62,6 +63,15 @@ void __init bcm63xx_nvram_init(void *addr)
 	if (crc != expected_crc)
 		pr_warn("nvram checksum failed, contents may be invalid (expected %08x, got %08x)\n",
 			expected_crc, crc);
+
+	/* Cable modems have a different NVRAM which is embedded in the eCos
+	 * firmware and not easily extractible, give at least a MAC address
+	 * pool.
+	 */
+	if (BCMCPU_IS_3368()) {
+		memcpy(nvram.mac_addr_base, hcs_mac_addr, ETH_ALEN);
+		nvram.mac_addr_count = 2;
+	}
 }
 
 u8 *bcm63xx_nvram_get_name(void)