sfc: fix unused-but-set-variable warning in efx_farch_filter_remove_safe

Thanks to some past refactor, 'spec' is not actually used in this
 function; the code using it moved to the callee efx_farch_filter_remove.
Remove the variable to fix a W=1 warning.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/farch.c

@@ -2589,7 +2589,6 @@ int efx_farch_filter_remove_safe(struct efx_nic *efx,
 	enum efx_farch_filter_table_id table_id;
 	struct efx_farch_filter_table *table;
 	unsigned int filter_idx;
-	struct efx_farch_filter_spec *spec;
 	int rc;
 
 	table_id = efx_farch_filter_id_table_id(filter_id);
@@ -2601,7 +2600,6 @@ int efx_farch_filter_remove_safe(struct efx_nic *efx,
 	if (filter_idx >= table->size)
 		return -ENOENT;
 	down_write(&state->lock);
-	spec = &table->spec[filter_idx];
 
 	rc = efx_farch_filter_remove(efx, table, filter_idx, priority);
 	up_write(&state->lock);