driver: icm426xx: Use calibration unit to set/get offset
driver: icm426xx: Use calibration unit to set/get offset

EC interface use constant (not range dependent) units to get/set
offsets. Use them in icm426xx driver.

BUG=b:177292639
BRANCH=hatch,nami,kukui,dedede,grunt,zork,octopus,volteer
TEST=compile

Change-Id: I6e6b1551464ea389db34646ba5b2bb553d683d7a
Signed-off-by: Gwendal Grignou <190c5a5edfcf62e0246559bf31fa7548674de3ad@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2657955
Reviewed-by: Ching-Kang Yen <c8fee4620c2902043a07aa1dce55b9338cfd358b@chromium.org>
Reviewed-by: Jean-Baptiste Maneyrol <abfe2be44ce1109c5b4ede022c1c0e9619655785@invensense.com>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec