mali400: use pegasus platform code from r3p2

r3p2 pegasus platform code has midas specific changes for
DVFS and also better support for Exynos4212.

This slightly improved the performance of the GPU.

Change-Id: I2ad903cd868e5c6bf1ce176aa43dfd056c19e5fc
n7100: disable threaded vsync

Change-Id: Ia8d7b7a08421e0a1798783f5d43127ed2fbb7d5b