msm: kgsl: Use consolidated power level for thermal limit

Ensure that thermal limits set by devfreq cooling framework,
limits framework and sysfs nodes (like gpu_max_clock) don't
overwrite each other, instead a consolidated (lowest of all)
limit is used as a final thermal limit. If this fails, fall back
to setting thermal_pwrlevel directly.

Change-Id: Ia6ec60e4881176da064c3cd5cf4ffd8e0a8e1046
Signed-off-by: Pranav Patel <quic_pranavp@quicinc.com>