soc/intel/quark: Add I2C support

Add the I2C driver.

TEST=Build and run on Galileo Gen2

Change-Id: I53fdac93667a8ffb2c2c8f394334de2dece63d66
Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-on: https://review.coreboot.org/14828
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
6 files changed