Have TMP006 sensor report -1 on sensor failure.

Temperature reading should be -1 on sensor failure.

Signed-off-by: Vic Yang <victoryang@chromium.org>

BUG=chrome-os-partner:8241
TEST="gpioset enable_vs 0" and "temps" gives "Error"
"gpioset enable_vs 1" and "temps" gives correct reading.

Change-Id: Ide82bd3433d3de12a749b0ee85f1ae1c6b12c5e5
1 file changed