kernel: measured rootfs as argument to build-kernel.sh

By convention the caller of tools/packaging/kernel/build-kernel.sh changes
the script behavior by passing arguments, whereas, for measured rootfs
it has used an environment variable (MEASURED_ROOTFS). This refactor
the script so that the caller now must pass the "-m" argument to enable
the build of the kernel with measured rootfs support.

Fixes #6674
Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>

tools/packaging/static-build/kernel/build.sh

@@ -39,7 +39,6 @@ sudo docker pull ${container_image} || \
 
 sudo docker run --rm -i -v "${repo_root_dir}:${repo_root_dir}" \
 	-w "${PWD}" \
-	--env MEASURED_ROOTFS="${MEASURED_ROOTFS:-}" \
 	"${container_image}" \
 	bash -c "${kernel_builder} -a ${ARCH} $* setup"