arm: asm: dma-mapping: added dma_free_coherent API

Added dma_free_coherent corresponding to the dma_alloc_coherent in
dma-mapping.h in order to free memory allocated using dma_alloc_coherent.
This API is used in dwc3 driver.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>

arch/arm/include/asm/dma-mapping.h

@@ -8,6 +8,8 @@
 #ifndef __ASM_ARM_DMA_MAPPING_H
 #define __ASM_ARM_DMA_MAPPING_H
 
+#define	dma_mapping_error(x, y)	0
+
 enum dma_data_direction {
 	DMA_BIDIRECTIONAL	= 0,
 	DMA_TO_DEVICE		= 1,
@@ -20,6 +22,11 @@ static inline void *dma_alloc_coherent(size_t len, unsigned long *handle)
 	return (void *)*handle;
 }
 
+static inline void dma_free_coherent(void *addr)
+{
+	free(addr);
+}
+
 static inline unsigned long dma_map_single(volatile void *vaddr, size_t len,
 					   enum dma_data_direction dir)
 {