wayland-drm: remove wl_buffer.damage

wayland-drm: remove wl_buffer.damage

This is a related fix for the Wayland change:

commit 83685c506e76212ae4e5cb722205d98d3b0603b9
Author: Kristian Høgsberg <krh@bitplanet.net>
Date:   Mon Mar 26 16:33:24 2012 -0400

    Remove wl_buffer.damage and simplify shm implementation

Apparently, this should also fix a memory leak. When wl_buffer.damage
was removed from Wayland and Mesa was not fixed, wl_buffer.destroy ended
up in the (empty) damage function instead of calling
wl_resource_destroy().

Spotted during build as:
  CC     wayland-drm-protocol.lo
wayland-drm.c:80:2: warning: initialization from incompatible pointer type
wayland-drm.c:82:1: warning: excess elements in struct initializer
wayland-drm.c:82:1: warning: (near initialization for 'drm_buffer_interface')

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>