hsr: rename debugfs file when interface name is changed

hsr interface has own debugfs file, which name is same with interface name.
So, interface name is changed, debugfs file name should be changed too.

Fixes: fc4ecaee

 ("net: hsr: add debugfs support for display node list")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>