ASoC: pxa: add COMPILE_TEST on SND_PXA2XX_SOC

It doesn't use asm header. We can add COMPILE_TEST
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/pxa/Kconfig

 config SND_PXA2XX_SOC
 	tristate "SoC Audio for the Intel PXA2xx chip"
-	depends on ARCH_PXA
+	depends on ARCH_PXA || COMPILE_TEST
 	select SND_PXA2XX_LIB
 	help
 	  Say Y or M if you want to add support for codecs attached to