[i2c/clock] add support for EPSON RTC-8583

RTC-8583 is time-of-day clock used in some SOHO routers. This clock has
only 2 bits for year values, but thanks to user SRAM it's possible to save
year value and keep it up to date via driver code.

Tested on Planex_MZK-W300NAG (SoC is RT2880)

Submitted by: Hiroki Mori <yamori83@yahoo.co.jp>
Differential Revision: https://reviews.freebsd.org/D12833