arch/tile: Do not use GFP_KERNEL for dma_alloc_coherent().

Feedback from fujita.tomonori@lab.ntt.co.jp.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>

arch/tile/kernel/pci-dma.c

@@ -35,8 +35,7 @@ void *dma_alloc_coherent(struct device *dev,
 	struct page *pg;
 	dma_addr_t addr;
 
-	/* Set GFP_KERNEL to ensure we have memory with a kernel VA. */
-	gfp |= GFP_KERNEL | __GFP_ZERO;
+	gfp |= __GFP_ZERO;
 
 	/*
 	 * By forcing NUMA node 0 for 32-bit masks we ensure that the