radeon/vcn: add VP9 dpb buffer size

The current FW has restricted the size to the worse case,
and the new dynamic dpb buffer support is on the way from
firmware side, we will change accordingly.

Signed-off-by: Leo Liu <leo.liu@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>

src/gallium/drivers/radeon/radeon_vcn_dec.c

@@ -1019,6 +1019,12 @@ static unsigned calc_dpb_size(struct radeon_decoder *dec)
 		dpb_size = MAX2(dpb_size, 30 * 1024 * 1024);
 		break;
 
+	case PIPE_VIDEO_FORMAT_VP9:
+		max_references = MAX2(max_references, 9);
+
+		dpb_size = (4096 * 3000 * 3 / 2) * max_references;
+		break;
+
 	default:
 		// something is missing here
 		assert(0);