staging: fsl-mc: bus: Drop warning

When updating the irq_chip and msi_domain_ops, the code checkes for
already present functions.
When more then one ITS controller are present in the system,
irq_chip and msi_domain_ops got already set and a warning is invoked.

This patch deletes the warning, as the funtions are just already set to
the needed callbacks.

Signed-off-by: Matthias Brugger <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/fsl-mc/bus/mc-msi.c

···
 	/*
 	 * set_desc should not be set by the caller
 	 */
-	if (WARN_ON(ops->set_desc))
-		return;
-
-	ops->set_desc = fsl_mc_msi_set_desc;
+	if (ops->set_desc == NULL)
+		ops->set_desc = fsl_mc_msi_set_desc;
 }
 
 static void __fsl_mc_msi_write_msg(struct fsl_mc_device *mc_bus_dev,
···
 	/*
 	 * irq_write_msi_msg should not be set by the caller
 	 */
-	if (WARN_ON(chip->irq_write_msi_msg))
-		return;
-
-	chip->irq_write_msi_msg = fsl_mc_msi_write_msg;
+	if (chip->irq_write_msi_msg == NULL)
+		chip->irq_write_msi_msg = fsl_mc_msi_write_msg;
 }
 
 /**