dma: mmp_tdma: Fix build for ARM64

sram_get_gpool is only used for legacy, non-DT MMP/PXA platforms. Provide
an empty version in order to build on ARM64.
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

include/linux/platform_data/dma-mmp_tdma.h

@@ -28,6 +28,13 @@ struct sram_platdata {
 	int granularity;
 };
 
+#ifdef CONFIG_ARM
 extern struct gen_pool *sram_get_gpool(char *pool_name);
+#else
+static inline struct gen_pool *sram_get_gpool(char *pool_name)
+{
+	return NULL;
+}
+#endif
 
 #endif /* __DMA_MMP_TDMA_H */