tegra3: scale cpu_g from 102MHz to 1500MHz.

(original commit by franciscofranco for grouper 3.1.10)
(org commit ID a9c916d5230ba74f3840b6c06a054f53264212bb)

Change-Id: I4f861f7507d5a0cd263d2b902bd99d5e5e7d50c6