usb-pd: Tell TCPC and PPC to both source Vconn
usb-pd: Tell TCPC and PPC to both source Vconn

BRANCH=none
BUG=b:72961003,b:72956593
TEST=verified with grunt that parade TCPC will no longer shut down when
PPC sources Vconn

Change-Id: I6c1cee4dd8a40a992813841ec227a6af04de5313
Signed-off-by: Jett Rink <9d4aef0593e6843318d99df31597fb6153b89787@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/935301

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