drm/bridge: ti-sn65dsi86: Fix kernel-doc typo ln_polr => ln_polrs

This fixes a kernel doc warning due to a typo:
  warning: Function parameter or member 'ln_polrs' not described in 'ti_sn_bridge'

Fixes: 5bebaead

 ("drm/bridge: ti-sn65dsi86: Implement lane reordering + polarity")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200612123003.v2.3.Ib616e311c48cc64b2cef11bd54d4a9cedc874bb1@changeid