wayland: use kernel drm_fourcc header
It removes libdrm dependency with waylandsink and wayland APIs. Using a certain backend other than drm backend has the advantage of using waylandsink without libdrm.
I saw that drm_fourcc.h had been changed from kernel header to libdrm header, realized that it gives some benefit to check the change of the header,(https://bugzilla.gnome.org/show_bug.cgi?id=773927) but I just wonder it might be worth to someone like me who has some platforms which do not use drm backend.