driver: fix ina219 shunt voltage calculation
driver: fix ina219 shunt voltage calculation

Currently shunt voltage register value is multiplied by 2
instead of 10 resulting in a shunt voltage value which is
5 times less.
Fix this by using the correct multiplier (10) value.

example:
Refer http://www.ti.com/lit/ds/symlink/ina219.pdf table 7 for
shunt voltage register format.
Notice that 40.00 mV (40,000uV) <=> 4000 reg value
giving us the *10 multiplication factor.

BRANCH=none
BUG=none
TEST=make -j4 buildall
TEST=verified that the shunt voltage reported by "ina"
console command looks correct on my hardware.

Signed-off-by: Virendra Kakade <89b6c96a2d4f324649ed9d006ee15e4870a19523@ni.com>
Change-Id: I76a21ae3b56336236826785ae6addc1982cc4885
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2094742
Reviewed-by: Nicolas Boichat <f3daba1cdc403799935674d3cd4b0e5bd1804232@chromium.org>
Tested-by: Nicolas Boichat <f3daba1cdc403799935674d3cd4b0e5bd1804232@chromium.org>
Commit-Queue: Nicolas Boichat <f3daba1cdc403799935674d3cd4b0e5bd1804232@chromium.org>

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