drivers: thermal: Snapshot of lmh cpu VDD driver from msm-4.19

Add a snapshot of limits cpu voltage cooling device driver changes
from msm-4.19. This is snapshot as of 'commit <603750db5e89>
("drivers: thermal: validate cdev sysfs cur_state request before
using it")'.

Change-Id: I3e8763df4e0a715407b955939f3d91b6c10f976a
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>