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

Fixes: 99ea37bd ("regulator: bd70528: Support ROHM BD70528 regulator block")
Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Link: https://lore.kernel.org/r/20191023121452.GA1812@localhost.localdomainSigned-off-by: Mark Brown <broonie@kernel.org>