The SDK does not ship the generic platform files. Use relative path for
GENERIC_PLATFORM_DIR to make it work. This points it at the files from
the feed directory instead of the base SDK path

Signed-off-by: Felix Fietkau <nbd@nbd.name>

BTF pointer data has a different size on 32 vs 64 bit targets,
and while the generated eBPF code works, the BTF data fails to validate
on mismatch

Signed-off-by: Felix Fietkau <nbd@nbd.name>

This fixes an issue where the kernel would pick up an incompatible target
libyaml for building host tools

Signed-off-by: Felix Fietkau <nbd@nbd.name>

In order to genererate suitable kernel headers, a 5.10 kernel tree is
prepared with a default config for mips. The arch is forced to mips in
order to avoid issues with inline asm on various architectures in a way
that doesn't involve relying on the host toolchain/headers.
It also has the advantage of supporting both endian types

Signed-off-by: Felix Fietkau <nbd@nbd.name>