drm/meson: Set GEM CMA functions with DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE

DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE sets the functions in
struct drm_driver to their defaults. No functional changes are
made.

v2:
	* update for DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200605073247.4057-27-tzimmermann@suse.de