r-car m2: support recent USB touchscreens
r-car m2: support recent USB touchscreens

We need HID_MULTITOUCH for modern external USB touchscreens
on Silk/Koelsch/Porter boards.

Change-Id: Ie0aea64ca7d0dd79a25da17b861502c1b70235df
Author: Yannick GICQUEL <394b8d77a9045b1dd8f163cc0bad885440b4a9e8@iot.bzh>
Signed-off-by: Manuel Bachmann <8b31ddffd2af8b3bdbf196f13021d221108ef2ad@iot.bzh>

igel-oss/meta-renesas,igel-oss/meta-renesas,igel-oss/meta-renesas