rename use_x11 to ozone_platform_x11

Ozone is default now in Chromium and non-Ozone/X11 (aka use_x11) is
deprecated. During the transition period use_x11 == ozone_platform_x11.

Bug: chromium:1096425
Change-Id: Ie3643360ec6607796533054bdedf8e2bb8e7e749
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/231650
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35040}

AUTHORS

diff --git a/AUTHORS b/AUTHORS
index 8096282..11da0f4 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -70,6 +70,7 @@
 Manish Jethani <manish.jethani@gmail.com>
 Martin Storsjo <martin@martin.st>
 Matthias Liebig <matthias.gcode@gmail.com>
+Maksim Sisov <msisov@igalia.com>
 Maxim Pavlov <pavllovmax@gmail.com>
 Maxim Potapov <vopatop.skam@gmail.com>
 Michael Iedema <michael@kapsulate.com>