Initial PINE A64-LTS support

Here's my WIP branch for the PINE A64-LTS, mainline u-boot crashes before starting the kernel:

U-Boot SPL 2018.05 (Sep 08 2018 - 15:35:14 +0000)
DRAM: 0 MiB
### ERROR ### Please RESET the board ###

This branch also depends on https://gitlab.com/postmarketOS/pmbootstrap/merge_requests/1693

device/device-pine-a64lts/APKBUILD

@@ -26,5 +26,5 @@ package() {
 
 }
 
-sha512sums="e9b2e2b501e92f4431cd6ed2ee41c74b5b21b1f5e265c804b1a54e397428a68bcdde37e00c3a0a4fa8e7358b0e681d5e0d5f2eb58b14bf6cc87b4229518c9ea8  deviceinfo
+sha512sums="b168306e0efd7d0a1d139d63d1a3c5ee44c656f128429ecdc8ae289aedf5f5267ed315ec6ce57c0da2dfacbcbd43a021760230defe36f62068d0937dfed13b1c  deviceinfo
 ef7d21144b8c33f80968a6a089dcc6b568abd54f66f30d21d5befc10e51217484440aa8edb1065cd871ffba7bc599f44502bb6d240ee01f59dc92706ec6eabfd  uboot-script.cmd"