ARM: dts: berlin: enable SD card reader and eMMC for the BG2Q DMP

Enable the SD Card reader and the internal eMMC on the Berlin BG2Q DMP
using two of the SDHCI nodes of the Berlin BG2Q.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>