arm: dma_alloc_coherent: malloc() -> memalign()

Even though the MMU/D-cache is off, some DMA engines still
expect strict address alignment.

For example, the incoming Faraday FTMAC110 & FTGMAC100 ethernet
controllers expect the tx/rx descriptors should always be aligned
to 16-bytes boundary.

Signed-off-by: Kuo-Jung Su <dantesu@faraday-tech.com>
CC: Albert ARIBAUD <albert.u.boot@aribaud.net>
diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 009863b..55a4e26 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -16,7 +16,7 @@
 
 static void *dma_alloc_coherent(size_t len, unsigned long *handle)
 {
-	*handle = (unsigned long)malloc(len);
+	*handle = (unsigned long)memalign(ARCH_DMA_MINALIGN, len);
 	return (void *)*handle;
 }