scale_rga memory leak

[qiuxuewen]

The framecontext is not released.

vf_scale_rga.c
static void rga_release_frame(void *opaque, uint8_t *data)
{
AVDRMFrameDescriptor *desc = (AVDRMFrameDescriptor *)data;
RGAFrameContext *framecontext = (RGAFrameContext *)opaque;
MppBuffer buffer = framecontext->buffer;
av_free(desc);
mpp_buffer_put(buffer);
av_buffer_unref(&framecontext->frame_group_ref);
av_free(framecontext);
}

[jjm2473]

Thanks！