KGSL: correct kgsl_pwrctrl gpu freq store.

*ROM firmware store 450mhz to gpuclk store after GPU is cool again.
this leave me locked on MAX 450Mhz.

So to hack it. i must use pwr->thermal_pwrlevel = level - 2;
in gpuclk store.

now i get 650Mhz and higher GPU freqs on higher temp.

Tested with all possible hard 3d heavy tests, all great.
Temp is holding < 78c

Conflicts:
	drivers/gpu/msm/kgsl_pwrctrl.c