x86/pci/dma: Fix gfp flags for coherent DMA memory allocation

Commit 6894258 reversed the order of gfp_flags adjustment in
dma_alloc_attrs() for x86 [arch/x86/kernel/pci-dma.c] As a result,
relevant flags set by dma_alloc_coherent_gfp_flags() are just
discarded and cause coherent DMA memory allocation failure on some
devices.

Fixes: 6894258 ("dma-mapping: consolidate dma_{alloc,free}_{attrs,coherent}")
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20150914073834.GA13077@xzibit.linux.bs1.fc.nec.co.jp
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/pci-dma.c

@@ -131,8 +131,8 @@ void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr,
 
 bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp)
 {
-	*gfp = dma_alloc_coherent_gfp_flags(*dev, *gfp);
 	*gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32);
+	*gfp = dma_alloc_coherent_gfp_flags(*dev, *gfp);
 
 	if (!*dev)
 		*dev = &x86_dma_fallback_dev;