MAINTAINERS: Add myself as reviewer for mgag200 and ast drivers

I've contributed to these two drivers, fixing bugs and performance
issues.
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230530142615.57014-1-jfalempe@redhat.com

MAINTAINERS

@@ -6407,6 +6407,7 @@ F:	drivers/gpu/drm/aspeed/
 DRM DRIVER FOR AST SERVER GRAPHICS CHIPS
 M:	Dave Airlie <airlied@redhat.com>
 R:	Thomas Zimmermann <tzimmermann@suse.de>
+R:	Jocelyn Falempe <jfalempe@redhat.com>
 L:	dri-devel@lists.freedesktop.org
 S:	Supported
 T:	git git://anongit.freedesktop.org/drm/drm-misc
@@ -6558,6 +6559,7 @@ F:	drivers/gpu/drm/panel/panel-mantix-mlaf057we51.c
 DRM DRIVER FOR MGA G200 GRAPHICS CHIPS
 M:	Dave Airlie <airlied@redhat.com>
 R:	Thomas Zimmermann <tzimmermann@suse.de>
+R:	Jocelyn Falempe <jfalempe@redhat.com>
 L:	dri-devel@lists.freedesktop.org
 S:	Supported
 T:	git git://anongit.freedesktop.org/drm/drm-misc