linux-kbuild: Fix cross-build regression
The upstream resolve_btfids
Makefile tries to always do a native
build, so it requires the same workaround as objtool
to cross-build it
while still building fixdep
natively. The initial addition of this
tool to linux-kbuild was missing the variables needed to build fixdep
correctly.
Additionally, resolve_btfids
builds libbpf, which builds fixdep
in its
own way. Add a patch to make it use the standard fixdep
build rule.
Fixes: edab15ab ("Install resolve_btfid tool")