busybox-initramfs: add support to update MACH_KERNEL for ATV1, simplyfing cleaning of update folder

Signed-off-by: Stephan Raue <stephan@openelec.tv>
Merge branch 'master' of github.com:OpenELEC/OpenELEC.tv into openelec-settings

Conflicts:
	packages/sysutils/busybox/init.d/06_systemconfig
Merge branch 'openelec-settings' of github.com:OpenELEC/OpenELEC.tv into openelec-settings