rtc: add support for Epson RTC-9701JE V4

Add support for the Epson RTC-9701JE SPI RTC device.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>