TBT: Correct is_cable_speed_gen2_capable function
TBT: Correct is_cable_speed_gen2_capable function

The is_cable_speed_gen2_capable() function should use information about PD
revision instead of checking the VDM version.

BUG=None
BRANCH=None
TEST=None

Signed-off-by: Tomasz Michalec <a547db31280d14f095c760a23a7523d0b1e55fe6@semihalf.com>
Change-Id: I95a8bf977020b3756e5c82fde523c8ae29c455aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3113970
Commit-Queue: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
Reviewed-by: Jeremy Bettis <4df7b5147fee087dca33c181f288ee7dbf56e022@chromium.org>
Reviewed-by: Abe Levkoy <2e1ad7039298f93262cf06bbb457275fb3e2ecb5@chromium.org>
Reviewed-by: Keith Short <f6d578f97033c25f1206cb57d52f358974c82954@chromium.org>

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