Up until now, the necessary scm availability check has not been
performed, leading to possible null pointer dereferences (which did
happen for me on RB1).

Fix that.

Fixes: 53bca371 ("thermal/drivers/qcom: Add support for LMh driver")
Cc: <stable@vger.kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20240308-topic-rb1_lmh-v2-2-bac3914b0fe3@linaro.org