r8152: combine PHY reset with set_speed

PHY reset is necessary after some hw settings. However, it would
cause the linking down, and so does the set_speed function. Combine
the PHY reset with set_speed function. That could reduce the frequency
of linking down and accessing the PHY register.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>