drm: fix issue copying supported plane formats
Originally on the first 1/4th of the plane formats were copied, leading
to problems if AR24/XR24 appears later in the list.
diff --git a/src/compositor-drm.c b/src/compositor-drm.c
index ba376eb..edeb0ab 100644
--- a/src/compositor-drm.c
+++ b/src/compositor-drm.c
@@ -1227,7 +1227,7 @@
sprite->compositor = ec;
sprite->count_formats = plane->count_formats;
memcpy(sprite->formats, plane->formats,
- plane->count_formats);
+ plane->count_formats * sizeof(plane->formats[0]));
drmModeFreePlane(plane);
wl_list_insert(&ec->sprite_list, &sprite->link);