drm/sun4i: tv: Include drm_atomic.h

Commit ec491291 ("drm/sun4i: tv: Merge mode_set into atomic_enable")
has introduced a call to drm_atomic_get_new_crtc_state(), but didn't
include drm_atomic.h.

On CONFIG_OF systems, this is fine because drm_atomic.h is included by
drm_of.h through drm_bridge.h. However, whenever CONFIG_OF isn't set, we
end up with a compilation error.

Fixes: ec491291 ("drm/sun4i: tv: Merge mode_set into atomic_enable")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220909093116.4141982-1-maxime@cerno.tech

drivers/gpu/drm/sun4i/sun4i_tv.c

@@ -14,6 +14,7 @@
 #include <linux/regmap.h>
 #include <linux/reset.h>
 
+#include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_of.h>
 #include <drm/drm_panel.h>