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 <mbrugger@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -37,9 +37,7 @@ static void fsl_mc_msi_update_dom_ops(struct msi_domain_info *info)
 	/*
 	 * set_desc should not be set by the caller
 	 */
-	if (WARN_ON(ops->set_desc))
-		return;
-
+	if (ops->set_desc == NULL)
 		ops->set_desc = fsl_mc_msi_set_desc;
 }
 
@@ -129,9 +127,7 @@ static void fsl_mc_msi_update_chip_ops(struct msi_domain_info *info)
 	/*
 	 * irq_write_msi_msg should not be set by the caller
 	 */
-	if (WARN_ON(chip->irq_write_msi_msg))
-		return;
-
+	if (chip->irq_write_msi_msg == NULL)
 		chip->irq_write_msi_msg = fsl_mc_msi_write_msg;
 }