drm/panel/panel-tpo-tpg110: Correct misnaming and supply missing param description

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/panel/panel-tpo-tpg110.c:94: warning: Function parameter or member 'panel_mode' not described in 'tpg110'
 drivers/gpu/drm/panel/panel-tpo-tpg110.c:372: warning: Function parameter or member 'connector' not described in 'tpg110_get_modes'

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201113134938.4004947-14-lee.jones@linaro.org