Armadillo500 Add support for Seiko Instruments S-35390A rtc over i2c.

The RTC chip Seiko Instruments S-35390A is connected to the Application
Processor over the second bus i2c with the hard coded address 0x30.

Signed-off-by: Alberto Panizzo <maramaopercheseimorto@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>