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/mcdi.h b/drivers/net/ethernet/sfc/mcdi.h
index c8f2cd5..6c58dbd 100644
--- a/drivers/net/ethernet/sfc/mcdi.h
+++ b/drivers/net/ethernet/sfc/mcdi.h
@@ -65,7 +65,7 @@
 	unsigned int n_attrs;
 };
 
-extern void efx_mcdi_init(struct efx_nic *efx);
+extern int efx_mcdi_init(struct efx_nic *efx);
 
 extern int efx_mcdi_rpc(struct efx_nic *efx, unsigned cmd,
 			const efx_dword_t *inbuf, size_t inlen,