ASoC: rsnd: fixup rsnd_dmapp_stop() return value

45a4394d03("ASoC: rsnd: use mod base common method on DMA phase3")
Exchanged "void rsnd_dmapp_stop()" to "int rsnd_dmapp_stop()",
but it returns inverted value. This patch fixup it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>