qemuboot: write native sysroot of qemu-helper into qemuboot.conf
Native sysroot of qemu-helper contains all required tools
(qemu-system and tunctl atm) for runqemu to work. It's not
removed by rm_dir and should always exist. It makes sense
to write it into qemuboot.conf to make runqemu to use it
as a default directory for native tools.
This should also speed up runqemu as it doesn't need to run
to run 'bitbake qemu-helper -e' to get its native sysroot.
[YOCTO #11266]
[YOCTO #11193]
Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
