refactor(mediatek): add new LPM API for further extension

Add new LPM API `mt_lp_rm_find_constraint` and `mt_lp_rm_run_constraint`
for further extension.

Signed-off-by: Liju-Clr Chen <liju-clr.chen@mediatek.com>
Change-Id: I8298811e03227285a7d086166edf9e87471f74b4