fuse: only update necessary attributes

fuse_update_attributes() refreshes metadata for internal use.

Each use needs a particular set of attributes to be refreshed, but
currently that cannot be expressed and all but atime are refreshed.

Add a mask argument, which lets fuse_update_get_attr() to decide based on
the cache_mask and the inval_mask whether a GETATTR call is needed or not.

Reported-by: Yongji Xie <xieyongji@bytedance.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>