thermal: arm: dra752: Remove TSHUT configuration

Technical Reference Manual [1] mandates that software should
not be configuring the thermal shutdown thresholds. Hence
removing TSHUT_CONFIG.

[1] http://www.ti.com/lit/ug/sprui30b/sprui30b.pdf



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