librem5 devkit: resurrect device support
This MR does:
- Updates kernel to 5.2-based kernel from Purism
- Updates mesa-purism-gc7000 to Mesa 19.1 + Purism patches
- Updates u-boot, ATF, and uuu to exact versions used by Purism for the PureOS images
- Builds the m4 firmware binary (instead of relying on prebuilt binary from Purism)
- Fixes some issues in and simplifies the uboot script for booting
Edited by Administrator