arm-nommu: remove the partial DMA_ATTR_NON_CONSISTENT support

The arm-nommu DMA code supports DMA_ATTR_NON_CONSISTENT allocations, but
does not provide a cache_sync operation.  This means any user of it
will never be able to actually transfer cache ownership and thus cause
coherency bugs.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NVladimir Murzin <vladimir.murzin@arm.com>

arch/arm/mm/dma-mapping-nommu.c

@@ -39,18 +39,7 @@ static void *arm_nommu_dma_alloc(struct device *dev, size_t size,
 				 unsigned long attrs)
 
 {
-	void *ret;
-
-	/*
-	 * Try generic allocator first if we are advertised that
-	 * consistency is not required.
-	 */
-
-	if (attrs & DMA_ATTR_NON_CONSISTENT)
-		return dma_direct_alloc_pages(dev, size, dma_handle, gfp,
-				attrs);
-
-	ret = dma_alloc_from_global_coherent(size, dma_handle);
+	void *ret = dma_alloc_from_global_coherent(size, dma_handle);
 
 	/*
 	 * dma_alloc_from_global_coherent() may fail because:
@@ -70,16 +59,9 @@ static void arm_nommu_dma_free(struct device *dev, size_t size,
 			       void *cpu_addr, dma_addr_t dma_addr,
 			       unsigned long attrs)
 {
-	if (attrs & DMA_ATTR_NON_CONSISTENT) {
-		dma_direct_free_pages(dev, size, cpu_addr, dma_addr, attrs);
-	} else {
-		int ret = dma_release_from_global_coherent(get_order(size),
-							   cpu_addr);
-
-		WARN_ON_ONCE(ret == 0);
-	}
+	int ret = dma_release_from_global_coherent(get_order(size), cpu_addr);
 
-	return;
+	WARN_ON_ONCE(ret == 0);
 }
 
 static int arm_nommu_dma_mmap(struct device *dev, struct vm_area_struct *vma,