axolotl: Drop OVERRIDE_RS_DRIVER

Remove RenderScript driver, as it has never been loaded anyways.

Original commit message:
* So, this one from ether can cause everything to get janky AF
  every time RenderScript is actually used, and finding one that
  actually loads (no missing symbols) AND actually works well is,
  well, challenging. The device works fine with the "normal"
  non-adreno driver in AOSP, so let's use that until/unless we find
  an actually working adreno driver.

Change-Id: I4ab19269eb49f5f2aed375d9055d68c1b9835f69