I think that is not really necessary, I have the kernel (from khadas github) with the mali driver for frame-buffer from amlogic buildroot that is working over 70 celsius,
these are the steps:
1) just disable the gpu cooling and gpucore into the linux thermal fsys,
2) then is necessary a little patch to the gpu cooling (the code return NULL instead int..)
3) then another little patch to the thermal driver from amlogic (I think that this is not necessary , I have to check beacuse I have changed that code for debug)
after these 2 or 3 steps when the temp go over the first trip point (70) all should be fine,
the gpufreq_get_requested_power is no more called.
The reason could be the mali driver that is not handling the request correctly.