arm: mvebu: turris_mox: Update defconfig

arm: mvebu: turris_mox: Update defconfig

Add gpio command to defconfig - this can be used to detect whether the
button is pressed or light LEDs.
Add DS1307 RTC driver and the date command.
Add CONFIG_WATCHDOG, so that U-Boot calls watchdog_reset.
Add CONFIG_MISC_INIT_R so that ethernet addresses are read from OTP
before network controller is initialized.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Stefan Roese <sr@denx.de>