sh: add earlycon support to j2_defconfig

Signed-off-by: Rich Felker <dalias@libc.org>

arch/sh/configs/j2_defconfig

@@ -21,6 +21,7 @@ CONFIG_INET=y
 CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
 CONFIG_NETDEVICES=y
+CONFIG_SERIAL_EARLYCON=y
 CONFIG_SERIAL_UARTLITE=y
 CONFIG_SERIAL_UARTLITE_CONSOLE=y
 CONFIG_I2C=y