DMAENGINE: define a dummy filter function for ste_dma40

All platform data has to be made conditional on CONFIG_STEDMA40
or we can provide a simple dummy filter functions as to avoid
cluttering the code with other #ifdef:s.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

arch/arm/plat-nomadik/include/plat/ste_dma40.h

@@ -162,6 +162,8 @@ struct stedma40_platform_data {
 	int				 disabled_channels[STEDMA40_MAX_PHYS];
 };
 
+#ifdef CONFIG_STE_DMA40
+
 /**
  * stedma40_filter() - Provides stedma40_chan_cfg to the
  * ste_dma40 dma driver via the dmaengine framework.
@@ -223,4 +225,21 @@ dma_async_tx_descriptor *stedma40_slave_mem(struct dma_chan *chan,
 						  direction, flags);
 }
 
+#else
+static inline bool stedma40_filter(struct dma_chan *chan, void *data)
+{
+	return false;
+}
+
+static inline struct
+dma_async_tx_descriptor *stedma40_slave_mem(struct dma_chan *chan,
+					    dma_addr_t addr,
+					    unsigned int size,
+					    enum dma_data_direction direction,
+					    unsigned long flags)
+{
+	return NULL;
+}
+#endif
+
 #endif