keyboard_scan: Modify factory test scan loop
keyboard_scan: Modify factory test scan loop

For KSO6 and KSO7 of NPCX don't support input, it cause
that "ectool kbfactorytest" show pass while the key on
these 2 pins actually are shorted. Instead of only scanning
previous pin, scan all the other pins to avoid this situation.

BUG=b:213120693
BRANCH=none
TEST=make sure pressing the keys on the KSO6 and KSO7 would
     let "ectool kbfactorytest" show which pins are shorted.

Signed-off-by: Sue Chen <7d23cdcf270f71747b77aeecc793a9342f6d5c9e@quanta.corp-partner.google.com>
Change-Id: I465a9306695c056d9fef18496770839d067fc752
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3367370
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