Lower voltage for gpu
writeback: I believe these defines were calculated with HZ=1000 in mind.
Since our devices are HZ=100 I hardcoded the values on this constants.
I'm not 100% sure if this code was made for HZ with 1000 but I couldn't
track it to understand clearly. Although I didn't see any drawback of
using this as it is now. If anyone knows the answer please chime in.

Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
removed 51mhz and 102mhz for tf201 devices (BETA)