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="d320598d0c265344890b72ce2ffe34741765d5606ddaefa0cc621b7116b28d34220523350b69c4c9cb8780ec0c918e36b80bd247720a4d079c97d740d84ebaff  deviceinfo
+sha512sums="c6f0ab5c8a5312614facbf6284c2a19b634636a1435e179e96be152004a9d7731ce2de898b898a1a84aeea5476e9b4f31bf717bf79e74f4be2030385d935f9b1  deviceinfo
 fc71acf937691b09f2ac9b8cd724af245555c90fdff6a1fd0e64c0cad04cfc0b46ff5dec61b3ff42e6b076b02e5cf2518089c54340c35a91c0b2b88731826492  uboot-script.cmd"