kernel-devsrc: Improve vdso-offsets handling for qemuriscv64

kernel-devsrc: Improve vdso-offsets handling for qemuriscv64

Fix:

kernel-devsrc-1.0-r0 do_package_qa: QA Issue: File /lib/modules/6.6.15-yocto-standard/build/include/generated/.compat_vdso-offsets.h.cmd in package kernel-devsrc contains reference to TMPDIR [buildpaths]

by adding to the list of files we do this with. Also drop the
conditional since rm -f handles this.

This only apppears for qemurisc*.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>