drm/bridge: ti-sn65dsi86: Fixup register names

Order registers by offset and rename bits & masks to match the
datasheet. This makes the driver a bit easier to grok and
cross-reference with the datasheet.

Changes in v3:
- Added to the set

Cc: Sandeep Panda <spanda@codeaurora.org>
Reviewed-by: Sandeep Panda <spanda@codeaurora.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180813213058.184821-3-sean@poorly.run