Whale: add whale_samus board overlay and TCS3414 driver.

TCS3414 is digital color sensor.

BUG=chrome-os-partner:28870
TEST=Manually,
Connect TCS3414 module to BB_I2C on Beaglebone
1. servod -b whale_samus
2. dut-control whale_color1_HSV
   It should return [H, S, V] color

   For Red, Green, Blue, the H value should be close to 0, 0.3, 0.6
   respectively. V should be correlated to brightness.

3. dut-control whale_color_timing:timing_100ms (or timing_400ms)
   See increasing V from whale_color1_HSV

4. dut-control whale_color_gain:gain_4x (or _16x, _64x)
   See increasing V from whale_color1_HSV

5. If the reading is digitally saturated, V will become 1.0.

6. Only one Tcs3414Device instance is initialized in debug log.

7. Restart servod, the V value should be restored to default
  (i.e., 12ms integ time + 1x ADC analog gain)

Change-Id: I0373ad7dfb186a3f191e996723bd2206874905d7
Reviewed-on: https://chromium-review.googlesource.com/199713
Reviewed-by: Todd Broch <tbroch@chromium.org>
Commit-Queue: Justin Chuang <jchuang@chromium.org>
Tested-by: Justin Chuang <jchuang@chromium.org>
3 files changed