samus: small change to support sensor offsets in EC
samus: small change to support sensor offsets in EC

BRANCH=smaug
BUG=chromium:506101
TEST=On samus, check we can set the offset and are taken into account.
Check the bias added is correct in the measurements.

Change-Id: I6cf06271ac080a47a008a342d9d108fd302241cc
Signed-off-by: Gwendal Grignou <190c5a5edfcf62e0246559bf31fa7548674de3ad@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/283164
Reviewed-by: Alec Berg <1a4429eeda29095a12e19a73405f80f5b7f37a63@chromium.org>

akappy7/ChromeOS_EC_LED_Diagnostics,md5555/ec,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,fourier49/BZ_DEV_EC,fourier49/BIZ_EC,coreboot/chrome-ec,md5555/ec,coreboot/chrome-ec,coreboot/chrome-ec,md5555/ec,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BZ_DEV_EC,fourier49/BIZ_EC,fourier49/BZ_DEV_EC,coreboot/chrome-ec,fourier49/BIZ_EC,md5555/ec,akappy7/ChromeOS_EC_LED_Diagnostics,fourier49/BIZ_EC,fourier49/BZ_DEV_EC