mfd: kempld: Use PLATFORM_DEVID_NONE instead of -1

Use the `PLATFORM_DEVID_NONE` constant instead of hard-coding -1
when creating a platform device.

No functional changes are intended.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240223195113.880121-5-andriy.shevchenko@linux.intel.comSigned-off-by: Lee Jones <lee@kernel.org>

drivers/mfd/kempld-core.c

@@ -109,7 +109,7 @@ static int kempld_register_cells_generic(struct kempld_device_data *pld)
 	if (pld->feature_mask & KEMPLD_FEATURE_MASK_UART)
 		devs[i++].name = kempld_dev_names[KEMPLD_UART];
 
-	return mfd_add_devices(pld->dev, -1, devs, i, NULL, 0, NULL);
+	return mfd_add_devices(pld->dev, PLATFORM_DEVID_NONE, devs, i, NULL, 0, NULL);
 }
 
 static struct resource kempld_ioresource = {