MAINTAINERS: Update feiyang,st7701 panel bindings converted as YAML

The feiyang,fy07024di26a30d.txt and sitronix,st7701.txt has been
converted to YAML schemas, update MAINTAINERS to match them again.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200403142453.25307-3-jagan@amarulasolutions.com