fdt: update bcm283x device tree sources to Linux 4.14 state

Upstream Linux has received a few device tree updates to the RPi
which we should propagate into the builtin U-Boot one as well to
gain hardware support.

This patch bumps the dts files to their 4.14 Linux counterparts
with the exception of sdhost on 32bit RPi versions. There we stay
with iproc as the sdhost driver is missing in U-Boot.

Signed-off-by: Alexander Graf <agraf@suse.de>