ASoC: MMP audio needs sram support

Building the pxa/mmp audio driver without support for the mmp
sram driver enabled results in this link error:

sound/built-in.o: In function `mmp_pcm_free_dma_buffers':
:(.text+0x3e734): undefined reference to `sram_get_gpool'
sound/built-in.o: In function `mmp_pcm_new':
:(.text+0x3e7c0): undefined reference to `sram_get_gpool'

The sram driver is cannot be manually enabled and needs to
be turned on by selecting MMP_SRAM from each module that
needs it, which is what this patch does.

Ideally, MMP should move over to the generic SRAM support, but
for the moment, we can avoid the build error.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/pxa/Kconfig

@@ -11,6 +11,7 @@ config SND_PXA2XX_SOC
 config SND_MMP_SOC
 	bool "Soc Audio for Marvell MMP chips"
 	depends on ARCH_MMP
+	select MMP_SRAM
 	select SND_SOC_GENERIC_DMAENGINE_PCM
 	select SND_ARM
 	help