This commit:
- bumps the Linux kernel to 6.18.18
- bumps the U-Boot to 2026.01
- switches to a stable glibc Bootlin external toolchain
The updated U-Boot should also fix the CI build of the board.
Fixes: https://gitlab.com/buildroot.org/buildroot/-/jobs/13458392712
Run-tested on the board.
Signed-off-by: Dong Wang <wangdong115@foxmail.com>
[Julien: add missing BR2_TARGET_UBOOT_NEEDS_GNUTLS=y]
Signed-off-by: Julien Olivain <ju.o@free.fr>