thermal: qcom: tsens: Allow number of sensors to come from DT

For platforms that has multiple copies of the TSENS hardware block it's
necessary to be able to specify the number of sensors per block in DeviceTree.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>