sfc: Downgrade EPERM messages from MCDI to debug

When running in an unprivileged function we expect some MC commands
to fail with permission errors. To avoid log spew downgrade these to
debug only.
Signed-off-by: NBert Kenward <bkenward@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/mcdi.c

@@ -1082,9 +1082,10 @@ void efx_mcdi_display_error(struct efx_nic *efx, unsigned cmd,
 		code = MCDI_DWORD(outbuf, ERR_CODE);
 	if (outlen >= MC_CMD_ERR_ARG_OFST + 4)
 		err_arg = MCDI_DWORD(outbuf, ERR_ARG);
-	netif_err(efx, hw, efx->net_dev,
-		  "MC command 0x%x inlen %d failed rc=%d (raw=%d) arg=%d\n",
-		  cmd, (int)inlen, rc, code, err_arg);
+	netif_printk(efx, hw, rc == -EPERM ? KERN_DEBUG : KERN_ERR,
+		     efx->net_dev,
+		     "MC command 0x%x inlen %zu failed rc=%d (raw=%d) arg=%d\n",
+		     cmd, inlen, rc, code, err_arg);
 }
 
 /* Switch to polled MCDI completions.  This can be called in various