rtc: bd70528: Add MODULE ALIAS to autoload module

The bd70528 RTC driver is probed by MFD driver. Add MODULE_ALIAS
in order to allow udev to load the module when MFD sub-device cell
for RTC is added.

I'm not sure if this is a bugfix or feature addition but I guess
fixes tag won't harm in this case.

Fixes: 32a4a4eb ("rtc: bd70528: Initial support for ROHM bd70528 RTC")
Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Link: https://lore.kernel.org/r/20191023114711.GA13954@localhost.localdomainSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-bd70528.c

@@ -491,3 +491,4 @@ module_platform_driver(bd70528_rtc);
 MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
 MODULE_DESCRIPTION("BD70528 RTC driver");
 MODULE_LICENSE("GPL");
+MODULE_ALIAS("platofrm:bd70528-rtc");