rockchip: Set config_store before qbuf

BUG=chrome-os-partner:33728
TEST='
build plugin lib
put it under /usr/local/lib/libv4l/plugins/
update kernel to https://chromium-review.googlesource.com/#/c/232587/5
run "./video_encode_accelerator_unittest 
--test_stream_data=./bear_320x192_40frames.yuv:320:192:11:/tmp/out.vp8:200000"
check /tmp/out.vp8
'

Change-Id: I5343e6832d8b96bc773cfe74475c98a4dc993cfa
Reviewed-on: https://chromium-review.googlesource.com/235602


Reviewed-by: Pawel Osciak <posciak@chromium.org>
Commit-Queue: Jeffy Chen <jeffy.chen@rock-chips.com>
Tested-by: Jeffy Chen <jeffy.chen@rock-chips.com>

libv4l-rockchip/libv4l-encplugin-rockchip.c

@@ -341,6 +341,8 @@ static int ioctl_qbuf_locked(struct encoder_context *ctx, int fd,
 	if (ret)
 		return ret;
 
+	/* TODO: change this to config_store after the header is updated. */
+	buffer->reserved2 = buffer->index + 1;
 	ret = SYS_IOCTL(fd, VIDIOC_QBUF, buffer);
 	if (ret == 0)
 		ctx->can_qbuf = false;