platform-msi: Allocate MSI device data on first use

Allocate the MSI device data on first invocation of the allocation function
for platform MSI private data.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211210221813.805529729@linutronix.de

drivers/base/platform-msi.c

@@ -204,6 +204,8 @@ platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
 			     irq_write_msi_msg_t write_msi_msg)
 {
 	struct platform_msi_priv_data *datap;
+	int err;
+
 	/*
 	 * Limit the number of interrupts to 2048 per device. Should we
 	 * need to bump this up, DEV_ID_SHIFT should be adjusted
@@ -218,6 +220,10 @@ platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
 		return ERR_PTR(-EINVAL);
 	}
 
+	err = msi_setup_device_data(dev);
+	if (err)
+		return ERR_PTR(err);
+
 	/* Already had a helping of MSI? Greed... */
 	if (!list_empty(dev_to_msi_list(dev)))
 		return ERR_PTR(-EBUSY);
@@ -229,7 +235,7 @@ platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec,
 	datap->devid = ida_simple_get(&platform_msi_devid_ida,
 				      0, 1 << DEV_ID_SHIFT, GFP_KERNEL);
 	if (datap->devid < 0) {
-		int err = datap->devid;
+		err = datap->devid;
 		kfree(datap);
 		return ERR_PTR(err);
 	}