virtio: rename virtqueue_add_buf_gfp to virtqueue_add_buf

Remove wrapper functions. This makes the allocation type explicit in
all callers; I used GPF_KERNEL where it seemed obvious, left it at
GFP_ATOMIC otherwise.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/tools/virtio/virtio_test.c b/tools/virtio/virtio_test.c
index 0740284..6bf95f9 100644
--- a/tools/virtio/virtio_test.c
+++ b/tools/virtio/virtio_test.c
@@ -161,7 +161,8 @@
 			if (started < bufs) {
 				sg_init_one(&sl, dev->buf, dev->buf_size);
 				r = virtqueue_add_buf(vq->vq, &sl, 1, 0,
-						      dev->buf + started);
+						      dev->buf + started,
+						      GFP_ATOMIC);
 				if (likely(r >= 0)) {
 					++started;
 					virtqueue_kick(vq->vq);