honeybuns: Notify hpd->pd converter of DP_CONFIG messages
honeybuns: Notify hpd->pd converter of DP_CONFIG messages

This CL is part of a fix to delay sending DP_ATTENTION messages until
after at least one DP CONFIG message has been received. Sending
DP_ATTENTION messages priot to DP_CONFIG can cauase some port partners
to abort alt-dp mode.

BRANCH=quiche
BUG=b:192051705
TEST=verifed on kasumi (grunt) that the display is extended correctly
following usbc hotplug events. Previously, this case was failing 1 out
of 3-4 times.

Signed-off-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@google.com>
Change-Id: I84a962b2f315df28eda290ebae452e41fd6e0b32
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3035786
Tested-by: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>
Reviewed-by: Diana Z <cb2016afc7183e5356c690dc63b4ba817470501a@chromium.org>
Reviewed-by: Abe Levkoy <2e1ad7039298f93262cf06bbb457275fb3e2ecb5@chromium.org>
Commit-Queue: Scott Collyer <7d40b3eb9e17bf55d972074a5e77a7ea4159f9dd@chromium.org>

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