staging: set msi_domain_ops as __ro_after_init

Marked msi_domain_ops structs as __ro_after_init when called only during init.
This protects the data structure from accidental corruption.
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jess Frazelle <me@jessfraz.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/fsl-mc/bus/irq-gic-v3-its-fsl-mc-msi.c

@@ -51,7 +51,7 @@ static int its_fsl_mc_msi_prepare(struct irq_domain *msi_domain,
 	return msi_info->ops->msi_prepare(msi_domain->parent, dev, nvec, info);
 }
 
-static struct msi_domain_ops its_fsl_mc_msi_ops = {
+static struct msi_domain_ops its_fsl_mc_msi_ops __ro_after_init = {
 	.msi_prepare = its_fsl_mc_msi_prepare,
 };