vaapi_encode: Respect driver quirks around buffer destruction

No longer leaks memory when used with a driver with the "render does
not destroy param buffers" quirk (i.e. Intel i965).

(cherry picked from commit 221ffca6)
Fixes ticket #5871.

libavcodec/vaapi_encode.c

@@ -385,7 +385,27 @@ static int vaapi_encode_issue(AVCodecContext *avctx,
         av_log(avctx, AV_LOG_ERROR, "Failed to end picture encode issue: "
                "%d (%s).\n", vas, vaErrorStr(vas));
         err = AVERROR(EIO);
-        goto fail_at_end;
+        // vaRenderPicture() has been called here, so we should not destroy
+        // the parameter buffers unless separate destruction is required.
+        if (ctx->hwctx->driver_quirks &
+            AV_VAAPI_DRIVER_QUIRK_RENDER_PARAM_BUFFERS)
+            goto fail;
+        else
+            goto fail_at_end;
+    }
+
+    if (ctx->hwctx->driver_quirks &
+        AV_VAAPI_DRIVER_QUIRK_RENDER_PARAM_BUFFERS) {
+        for (i = 0; i < pic->nb_param_buffers; i++) {
+            vas = vaDestroyBuffer(ctx->hwctx->display,
+                                  pic->param_buffers[i]);
+            if (vas != VA_STATUS_SUCCESS) {
+                av_log(avctx, AV_LOG_ERROR, "Failed to destroy "
+                       "param buffer %#x: %d (%s).\n",
+                       pic->param_buffers[i], vas, vaErrorStr(vas));
+                // And ignore.
+            }
+        }
     }
 
     pic->encode_issued = 1;