ceph: print dentry offset in hex and fix xattr_version type

In the debug logs about the di->offset or ctx->pos it is in hex
format, but some others are using the dec format. It is a little
hard to read.

For the xattr version, it is u64 type, using a shorter type may
truncate it.

Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>