rtc: rv3028: make rv3028 probeable from userspace

With this commit, it will be possible to bind a rv3028 device from
userspace

This is done by:
echo rtc-rv3028 0x52 > /sys/bus/i2c/devices/i2c-XX/new_device

Signed-off-by: Johannes Kirchmair <johannes.kirchmair@sigmatek.at>
Link: https://lore.kernel.org/r/20230327085550.1721861-1-johannes.kirchmair@sigmatek.at


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>