TCPMv2: Correct PD 3.0 reply when SVDM isn't supported
TCPMv2: Correct PD 3.0 reply when SVDM isn't supported

In PD 3.0, a DUT must reply with Not_Supported when a SVDM isn't
supported. Note that PD 2.0 is still perfectly welcome to send a NAK
reply for this case.

BRANCH=None
BUG=b:181194535
TEST=with follow-on CL, verify TD.PD.VNDI3.E3 VDM Identity passes

Signed-off-by: Diana Z <cb2016afc7183e5356c690dc63b4ba817470501a@chromium.org>
Change-Id: Ie3b554cca017494b86342df1e9149b4452c83852
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2881028
Reviewed-by: Abe Levkoy <2e1ad7039298f93262cf06bbb457275fb3e2ecb5@chromium.org>

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