drivers: thermal: lmh-dcvsh: Register cooling device for all CPUs

CPU cooling device handles core isolation of a core as a last
mitigation. In order to place core isolation on individual CPU, it has
to be registered as a individual cooling device. Registering it as a
related CPU of a single cooling device won't allow individual CPU core
isolation.

LMH DCVSh driver now registers each CPU as a separate cooling device and
aggregates the frequency request for the related CPUs before sending to
the hardware.

Change-Id: Ia1c12490d4a694174a6d40ea63fdc63889c135d0
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>