arch_topology: Sanity check cpumask in thermal pressure update

Occasionally during boot the Qualcomm cpufreq driver was able to cause
an invalid memory access in topology_update_thermal_pressure() on the
line:

	if (max_freq <= capped_freq)

It turns out that this was caused by a race, which resulted in the
cpumask passed to the function being empty, in which case
cpumask_first() will return a cpu beyond the number of valid cpus, which
when used to access the per_cpu max_freq would return invalid pointer.

The bug in the Qualcomm cpufreq driver is being fixed, but having a
sanity check of the arguments would have saved quite a bit of time and
it's not unlikely that others will run into the same issue.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Message-Id: <20220118185612.2067031-2-bjorn.andersson@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>