dt-bindings: display: simple: add CDTech S070PWS19HP-FC21 and S070SWV29HG-DC44

Add the CDTech Electronics displays S070PWS19HP-FC21 (7.0" WSVGA) and
S070SWV29HG-DC44 (7.0" WVGA) to the panel-simple compatible list.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200612072219.13669-2-matthias.schiffer@ew.tq-group.com