ARM: dts: rmobile: Extract SDHI extras on H3, M3W, M3N Salvator-X

The SDHI nodes are missing features supported in upstream U-Boot,
like mode support properties. Pull the extras into U-Boot specific
DT until it hits mainline Linux, to make syncing of DTs easier.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
---
V2: Rebase on u-boot/master