odroid-c2: Populate serial# environment variable from efuse

board/amlogic/odroid-c2/odroid-c2.c

@@ -24,6 +24,7 @@ int board_init(void)
 int misc_init_r(void)
 {
 	u8 mac_addr[EFUSE_MAC_SIZE];
+	char serial[EFUSE_SN_SIZE];
 	ssize_t len;
 
 	/* Set RGMII mode */
@@ -50,5 +51,12 @@ int misc_init_r(void)
 			eth_setenv_enetaddr("ethaddr", mac_addr);
 	}
 
+	if (!getenv("serial#")) {
+		len = meson_sm_read_efuse(EFUSE_SN_OFFSET, serial,
+			EFUSE_SN_SIZE);
+		if (len == EFUSE_SN_SIZE) 
+			setenv("serial#", serial);
+	}
+
 	return 0;
 }