vhost: Move VHOST_NET_FEATURES to net.c

vhost.h should not depend on device specific marcos like
VHOST_NET_F_VIRTIO_NET_HDR and VIRTIO_NET_F_MRG_RXBUF.

Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 354665a..06b2447 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -59,6 +59,12 @@
 #define VHOST_DMA_IS_DONE(len) ((len) >= VHOST_DMA_DONE_LEN)
 
 enum {
+	VHOST_NET_FEATURES = VHOST_FEATURES |
+			 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
+			 (1ULL << VIRTIO_NET_F_MRG_RXBUF),
+};
+
+enum {
 	VHOST_NET_VQ_RX = 0,
 	VHOST_NET_VQ_TX = 1,
 	VHOST_NET_VQ_MAX = 2,