virtio: console: Fix return type for get_inbuf()

get_inbuf() returns void *.  There's no reason to return void pointers
instead of the correct struct port_buffer *.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

drivers/char/virtio_console.c

@@ -348,7 +348,7 @@ static struct port_buffer *alloc_buf(size_t buf_size)
 }
 
 /* Callers should take appropriate locks */
-static void *get_inbuf(struct port *port)
+static struct port_buffer *get_inbuf(struct port *port)
 {
 	struct port_buffer *buf;
 	struct virtqueue *vq;