MAINTAINERS: adjust file entry in HIMAX HX83112B TOUCHSCREEN SUPPORT

MAINTAINERS: adjust file entry in HIMAX HX83112B TOUCHSCREEN SUPPORT

Commit a311c777f298 ("dt-bindings: touchscreen: consolidate simple touch
controller to trivial-touch.yaml") aggregates a few touchscreen yaml files
into a common trivial-touch.yaml, but misses to adjust the reference in
HIMAX HX83112B TOUCHSCREEN SUPPORT, which refers to the removed file
himax,hx83112b.yaml.

Make HIMAX HX83112B TOUCHSCREEN SUPPORT refer to trivial-touch.yaml, in
order to inform the maintainer on changes to the device-tree binding
relevant to that hardware driver.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Link: https://patch.msgid.link/20251110054733.441893-1-lukas.bulwahn@redhat.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>