rtc: m48t35: remove SGI-IP27 kludge

With the IOC3 MFD driver it's no longer necessary to special case SGI-IP27.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Link: https://lore.kernel.org/r/20200309123514.15543-1-tsbogend@alpha.franken.de


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