[ryu_sh] Add option to flash the sensor hub
[ryu_sh] Add option to flash the sensor hub

servo is already aware of the sensor hub.
Using samus_pd as an example, set the proper argument to flash
an image to the sensor hub.

BUG=chrome-os-partner:30801
BRANCH=None
TEST=None

Change-Id: I0c8465d1e34d515224675957c3e8482392585a56
Signed-off-by: Gwendal Grignou <190c5a5edfcf62e0246559bf31fa7548674de3ad@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/209232
Reviewed-by: Randall Spangler <62698fdbb84d1779579ee80c3f39fac22017e5bc@chromium.org>

mtk09422/chromiumos-platform-ec,akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BZ_DEV_EC,coreboot/chrome-ec,md5555/ec,fourier49/BIZ_EC,fourier49/BIZ_EC,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,fourier49/BIZ_EC,mtk09422/chromiumos-platform-ec,coreboot/chrome-ec,md5555/ec,coreboot/chrome-ec,coreboot/chrome-ec,longsleep/ec,akappy7/ChromeOS_EC_LED_Diagnostics,md5555/ec,longsleep/ec,eatbyte/chromium-ec,longsleep/ec,md5555/ec,longsleep/ec,thehobn/ec,thehobn/ec,eatbyte/chromium-ec,fourier49/BIZ_EC,eatbyte/chromium-ec,thehobn/ec,fourier49/BZ_DEV_EC,fourier49/BZ_DEV_EC,mtk09422/chromiumos-platform-ec,eatbyte/chromium-ec,akappy7/ChromeOS_EC_LED_Diagnostics,mtk09422/chromiumos-platform-ec,thehobn/ec,coreboot/chrome-ec,fourier49/BZ_DEV_EC