manta: Enable prefetch optimizations

 * Set CFLAGS to enable prefetch optimizations in Skia and Webkit

Change-Id: Id3ff93392b1a7be8cde398ef55b1cf65f34be2e2
manta: Enable WebGL

Change-Id: Iada49f1ea604182835753a48ba8dc115b86ff18d
manta: add /d/kbase_carveout to dumpstate

Add /d/kbase_carveout to show how many pages have been allocated
by the gpu out of the carveout or system memory.

Change-Id: I2aa58e812a8d50c9505180ef52f579512445df0f