sfc: give ef10 its own rwsem in the filter table instead of filter_lock

efx->filter_lock remains in place for use on farch, but EF10 now ignores it.
EFX_EF10_FILTER_FLAG_BUSY is no longer needed, hence it is removed.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/efx.c

@@ -1783,7 +1783,6 @@ static int efx_probe_filters(struct efx_nic *efx)
 {
 	int rc;
 
-	spin_lock_init(&efx->filter_lock);
 	init_rwsem(&efx->filter_sem);
 	mutex_lock(&efx->mac_lock);
 	down_write(&efx->filter_sem);

drivers/net/ethernet/sfc/net_driver.h

@@ -843,7 +843,7 @@ struct efx_rss_context {
  * @loopback_mode: Loopback status
  * @loopback_modes: Supported loopback mode bitmask
  * @loopback_selftest: Offline self-test private state
- * @filter_sem: Filter table rw_semaphore, for freeing the table
+ * @filter_sem: Filter table rw_semaphore, protects existence of @filter_state
  * @filter_lock: Filter table lock, for mere content changes
  * @filter_state: Architecture-dependent filter table state
  * @rps_mutex: Protects RPS state of all channels