sfc: Make efx_mcdi_init() call efx_mcdi_handle_assertion()

This should probably be done during MCDI initialisation for any NIC.
Change efx_mcdi_init() to return an error code.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
diff --git a/drivers/net/ethernet/sfc/siena.c b/drivers/net/ethernet/sfc/siena.c
index b5d5568..3dca771 100644
--- a/drivers/net/ethernet/sfc/siena.c
+++ b/drivers/net/ethernet/sfc/siena.c
@@ -210,10 +210,7 @@
 	efx_reado(efx, &reg, FR_AZ_CS_DEBUG);
 	efx->port_num = EFX_OWORD_FIELD(reg, FRF_CZ_CS_PORT_NUM) - 1;
 
-	efx_mcdi_init(efx);
-
-	/* Recover from a failed assertion before probing */
-	rc = efx_mcdi_handle_assertion(efx);
+	rc = efx_mcdi_init(efx);
 	if (rc)
 		goto fail1;