samus_pd: Request different DP pin modes including multi-function.

Previously samus_pd just picked pin mode E without regard to what the
UFP was requesting.  This change surveys the UFP's DP pin capabilities
and then requests the appropriate pin config.

Additionally if the UFP supports multi-function and has preferred it
during the initial DP status message, samus will configure its
type-c mux in 'dock' mode.

Signed-off-by: Todd Broch <tbroch@chromium.org>

BRANCH=samus
BUG=chrome-os-partner:38728
TEST=manual,
1. hoho + samus, pin mode = 'C'
2. dingdong + samus, pin mode = 'E'.
3. apple type-C HDMI multiport + samus, pin mode = 'D' and USB device
   enumerates as SuperSpeed.
4. plankton + samus w/ patch asserting alternate mode with
   multi-function preferred sets config to 'F' now and only drives DP
   out on 2 lanes w/ other two allowing USB key to be seen.

Change-Id: Ie4764c33f108e8a88f0052b64ddb96cb92e5a78b
Reviewed-on: https://chromium-review.googlesource.com/267796
Commit-Queue: Todd Broch <tbroch@chromium.org>
Tested-by: Todd Broch <tbroch@chromium.org>
Reviewed-by: Alec Berg <alecaberg@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

0 files changed, 0 insertions, 0 deletions