gl/dispmanx: assign render_rect to window before window_resize
requested to merge avdb/gst-plugins-base:dispmanx-origin-renderrectangle-is-not-respected into master
If the render_rect for a dispmanx display is set after calling
window_resize the resize defaults to the dp_width and dp_height to
determine the location of the render rectangle instead of the correct
dimensions that should be set on the window_egl.
Introduced by !1030 (merged)