dt-bindings: cpufreq: cpufreq-qcom-hw: Add QCM2290

Document the OSM CPUFREQ_HW present on QCM2290, featuring just one
lonely frequency domain.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>