drm/ttm: Fix cached TTM page allocation.

This patch fixes a regression introduced with the pool page allocator
in the event that there are no highmem pages (for example x86_64),
in which case cached page allocation would fail.

Tested with the vmwgfx driver on a 64-bit vm.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/ttm/ttm_page_alloc.c

@@ -671,7 +671,7 @@ int ttm_get_pages(struct list_head *pages, int flags,
 		if (flags & TTM_PAGE_FLAG_DMA32)
 			gfp_flags |= GFP_DMA32;
 		else
-			gfp_flags |= __GFP_HIGHMEM;
+			gfp_flags |= GFP_HIGHUSER;
 
 		for (r = 0; r < count; ++r) {
 			p = alloc_page(gfp_flags);