BCM2837 has two mmc interfaces: sdhost and sdhci. On Raspberry Pi 3, sdhost is
normally used for SD card/MMC flash and sdhci for the wireless interface.
Barebox currently only has a driver for sdhci, so we disable the sdhost
interface and remap the pins so that the sdhci has access to the SD card/MMC
flash.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Since we now support the miniuart, enable it as the default stdout port.
With this change the device tree overlay to switch the miniuart to bluetooth is
no longer necessary.

Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

This adds basic support at the same feature level as the other
supported raspberry pi boards.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Roland Hieber <r.hieber@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>