ASoC: cirrus: Enable compile test builds

The core support for ep93xx (currently only the DMA driver) does not
depend on the architecture at all and everything else has more strict
dependencies so enable compile test builds for improved build coverage.
Signed-off-by: NMark Brown <broonie@linaro.org>

sound/soc/cirrus/Kconfig

 config SND_EP93XX_SOC
 	tristate "SoC Audio support for the Cirrus Logic EP93xx series"
-	depends on ARCH_EP93XX && SND_SOC
+	depends on (ARCH_EP93XX || COMPILE_TEST) && SND_SOC
 	select SND_SOC_GENERIC_DMAENGINE_PCM
 	help
 	  Say Y or M if you want to add support for codecs attached to