net: bridge: mrp: Update ring transitions.

According to the standard IEC 62439-2, the number of transitions needs
to be counted for each transition 'between' ring state open and ring
state closed and not from open state to closed state.

Therefore fix this for both ring and interconnect ring.

Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>