beagle-x15: Update kernel prebuilts, add GPU driver am: 5dff716b9b
am: 70c8a3c0ac

Change-Id: I8cf67a6370080575639fe1493f1f7f88565816e1
tree: 2337607d01e90808639d47a0ea2677a2172f81a9
  1. 4.14/