Fix the AUX_CMD_SEND bit for ti,sn65dsi86 bridge chip. With wrong
value the dpcd aux transactions with eDP panel are failing.

Signed-off-by: Sandeep Panda <spanda@codeaurora.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20181130092745.4219-1-spanda@codeaurora.org