sfc_ef100: actually perform resets

In ef100_reset(), make the MCDI call to do the reset.
Also, do a reset at start-of-day during probe, to put the function in
 a clean state.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>