thermal: ti-soc-thermal: Remove redundant code

ti_thermal_expose_sensor always takes the
devm_thermal_zone_of_sensor_register call for registration
with the device tree nodes present for all the bandgap sensors
for omap3/4/5 and dra7 family. There are large chunks of unused
code. Removing all of them.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>