Add clock for i2c
Enable i2c1
Set the i2c bus speed to 100KHz
Add the following i2c peripherals
* ds1339 RTC
* 24c32 EEPROM
* max1619 temperature monitor
* ltc2497 ADC
  * Add a fixed regulator for the ADC's Vref.

This requires Dinh Nguyen's Stratix10 clock driver
("clk: socfpga: stratix10: add clock driver for Stratix10 platform")
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>