render: remove wl_drm support from wlr_renderer

Everything needs to go through the unified wlr_buffer interface
now.

If necessary, there are two ways support for
EGL_WL_bind_wayland_display could be restored by compositors:

- Either by using GBM to convert back EGL Wayland buffers to
  DMA-BUFs, then wrap the DMA-BUF into a wlr_buffer.
- Or by wrapping the EGL Wayland buffer into a special wlr_buffer
  that doesn't implement any wlr_buffer_impl hook, and special-case
  that buffer type in the renderer.

include/wlr/render/wlr_renderer.h

@@ -80,16 +80,6 @@ void wlr_render_quad_with_matrix(struct wlr_renderer *r,
  */
 const uint32_t *wlr_renderer_get_shm_texture_formats(
 	struct wlr_renderer *r, size_t *len);
-/**
- * Returns true if this wl_buffer is a wl_drm buffer.
- */
-bool wlr_renderer_resource_is_wl_drm_buffer(struct wlr_renderer *renderer,
-	struct wl_resource *buffer);
-/**
- * Gets the width and height of a wl_drm buffer.
- */
-void wlr_renderer_wl_drm_buffer_get_size(struct wlr_renderer *renderer,
-	struct wl_resource *buffer, int *width, int *height);
 /**
  * Get the DMA-BUF formats supporting sampling usage. Buffers allocated with
  * a format from this list may be imported via wlr_texture_from_dmabuf.