drm/msm/dp: drop unused parser definitions

Drop several unused and obsolete definitions from the dp_parser module.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Reviewed-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/576110/
Link: https://lore.kernel.org/r/20240126-dp-power-parser-cleanup-v3-1-098d5f581dd3@linaro.org