thermal: tsens: Add the SROT address map

On platforms whose device trees specify two address spaces for TSENS, the
second one points to the SROT registers. Initialise the SROT map on those
platforms.

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>