agp: drop vmalloc flag.

Since the code that was too ugly to live is upstream, we can use it now,
instead of rolling our own.

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
index 4b51982..4e41441 100644
--- a/drivers/char/agp/generic.c
+++ b/drivers/char/agp/generic.c
@@ -97,20 +97,18 @@
 void agp_alloc_page_array(size_t size, struct agp_memory *mem)
 {
 	mem->pages = NULL;
-	mem->vmalloc_flag = false;
 
 	if (size <= 2*PAGE_SIZE)
 		mem->pages = kmalloc(size, GFP_KERNEL | __GFP_NORETRY);
 	if (mem->pages == NULL) {
 		mem->pages = vmalloc(size);
-		mem->vmalloc_flag = true;
 	}
 }
 EXPORT_SYMBOL(agp_alloc_page_array);
 
 void agp_free_page_array(struct agp_memory *mem)
 {
-	if (mem->vmalloc_flag) {
+	if (is_vmalloc_addr(mem->pages)) {
 		vfree(mem->pages);
 	} else {
 		kfree(mem->pages);