ectool: print unsigned version of sensor values
ectool: print unsigned version of sensor values

Some sensors use the full 16-bits for an unsigned number; print out
the unsigned interpretation of the signed value as well in ectool.

Example output:
Timestamp:10e87e
Timestamp:fdbde87d
Sensor 1: -96   -8027   -1559 (as uint16: 4294967200    4294959269 4294965737)
Timestamp:2c77e87f
Sensor 1: -98   -8025   -1568 (as uint16: 4294967198    4294959271 4294965728)
Timestamp:61bee880
Timestamp:5b38e880
Sensor 1: -97   -8026   -1568 (as uint16: 4294967199    4294959270 4294965728)
Timestamp:8a10e881
Sensor 1: -98   -8025   -1560 (as uint16: 4294967198    4294959271 4294965736)

BRANCH=none
BUG=b:138096172,
TEST=builds

Change-Id: Ifa0eef9721a64b1b9e21624ee7113fbf949adbf7
Signed-off-by: Jett Rink <9d4aef0593e6843318d99df31597fb6153b89787@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1726735
Reviewed-by: Daisuke Nojiri <fd5f93af191bf7e8f73ea71cc3c0f66b41b1dd49@chromium.org>

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