Add Python module to support Linux i2c-dev

This change adds I2C bus module to access Linux i2c-dev I2C_RDWR function.

BUG=chromium:402358
TEST=manual
  servod -b whale_samus
  dut-control -s servo_host dut_flaga:on dut_flaga
  dut-control -s servo_host dut_flaga:off dut_flaga

Change-Id: I0e204d5c84fa8790423ba88d56bda2c3654183d0
Reviewed-on: https://chromium-review.googlesource.com/211597
Commit-Queue: Rong Chang <rongchang@chromium.org>
Tested-by: Rong Chang <rongchang@chromium.org>
Reviewed-by: Justin Chuang <jchuang@chromium.org>
Reviewed-by: Dean Liao <deanliao@chromium.org>
3 files changed