8042: Add some keyboard inhibit unit tests
8042: Add some keyboard inhibit unit tests

Verify the I8042_DIS_KB and I8042_ENA_KB commands work as expected.
Also test the behavior when keys are pressed while the controller is
inhibited. This uncovered wrong behavior.

BUG=b:242886255
BRANCH=none
TEST=run unit tests

Signed-off-by: Raul E Rangel <9a9c998e11a2655b1de9a05eeeef5f710c0dc7ed@chromium.org>
Change-Id: I13b795d81715d1d51fa3f7efb2c1d9246b43e8c4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3843090
Reviewed-by: Yuval Peress <50dc11c009bd4d7e9d9d15a383c1743ce5ee82ef@google.com>
Reviewed-by: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>

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