servo_v4: The polarity is based on the flags in SRC DTS mode

When the port in SRC DTS mode, it should not perform the polarity
detection. The polarity is predetermined, as a board-specific
setting. In the servo case, the polarity is based on the flags.

This CL changes the protocol layer to check the port in SRC DTS mode
and call the board-specific function board_get_src_dts_polarity()
for the polarity.

BRANCH=servo
BUG=b:140876537
TEST=Configed servo as srcdts and unflipped direction:
> cc srcdts cc2

Verified the power negotiation good and detected the correct polarity:
> pd 1 state
Port C1 CC2, Ena - Role: SRC-UFP State: SRC_READY, Flags: 0x415e

Without this patch, it detected the wrong polarity and the power
negotiation failed:
> pd 1 state
Port C1 CC1, Ena - Role: SRC-DFP State: SRC_DISCOVERY, Flags: 0x10608

Change-Id: I32c5dfffeaeb20a21db1417f3a1c98566b7f5e38
Signed-off-by: Wai-Hong Tam <waihong@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1891255
Reviewed-by: Jett Rink <jettrink@chromium.org>
Commit-Queue: Sean Abraham <seanabraham@chromium.org>
(cherry picked from commit 3c1eff2e293adeca40c0c919e63db4c62b89de41)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1902098

0 files changed, 0 insertions, 0 deletions