vdpa: Fix some coding style issues

Fix some code indent issues and following checkpatch warning:

WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
371: FILE: include/linux/vdpa.h:371:
+static inline void vdpa_get_config(struct vdpa_device *vdev, unsigned offset,

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20210831103634.33-5-xieyongji@bytedance.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>