cpufreq: qcom-hw: Update logic to detect turbo frequency

The core count read back from the each domain's look up table serves
as an indicator for the onset of the turbo frequency and not accurate
representation of number of cores in a paticular domain. Update turbo
detection logic accordingly to add support for SM8150 SoCs.

Signed-off-by: Sibi Sankar <sibis@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>