Add DRM_PRIME Format Handling and Display for RockChip MPP decoders

This commit allows to use the AV_PIX_FMT_DRM_PRIME newly introduced
format in ffmpeg that allows decoders to provide an AVDRMFrameDescriptor
struct.

That struct holds dmabuf fds and information allowing zerocopy rendering
using KMS / DRM Atomic.

This has been tested on RockChip ROCK64 device.

options/options.c

@@ -111,6 +111,7 @@ const struct m_opt_choice_alternatives mp_hwdec_names[] = {
     {"d3d11va-copy",HWDEC_D3D11VA_COPY},
     {"rpi",         HWDEC_RPI},
     {"rpi-copy",    HWDEC_RPI_COPY},
+    {"rkmpp",       HWDEC_RKMPP},
     {"mediacodec",  HWDEC_MEDIACODEC},
     {"mediacodec-copy",HWDEC_MEDIACODEC_COPY},
     {"cuda",        HWDEC_CUDA},
@@ -181,6 +182,7 @@ static const m_option_t mp_vo_opt_list[] = {
     OPT_STRING_VALIDATE("drm-connector", drm_connector_spec,
                         0, drm_validate_connector_opt),
     OPT_INT("drm-mode", drm_mode_id, 0),
+    OPT_INT("drm-overlay", drm_overlay_id, 0),
 #endif
     OPT_STRING_VALIDATE("opengl-hwdec-interop", gl_hwdec_interop, 0,
                         ra_hwdec_validate_opt),

options/options.h

@@ -57,6 +57,7 @@ typedef struct mp_vo_opts {
     // vo_drm
     char *drm_connector_spec;
     int drm_mode_id;
+    int drm_overlay_id;
 } mp_vo_opts;
 
 struct mp_cache_opts {