ASoC: fix compile breakage if CONFIG_SH_DMA_API=y && CONFIG_SND_SIU_MIGOR!=n

Audio on Migo-R cannot work if CONFIG_SH_DMA_API=y, but compilation should not
break anyway.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/sh/Kconfig b/sound/soc/sh/Kconfig
index a86696b..1066749 100644
--- a/sound/soc/sh/Kconfig
+++ b/sound/soc/sh/Kconfig
@@ -29,6 +29,7 @@
 config SND_SOC_SH4_SIU
 	tristate
 	depends on (SUPERH || ARCH_SHMOBILE) && HAVE_CLK
+	select DMA_ENGINE
 	select DMADEVICES
 	select SH_DMAE