As per latest Raspberry Pi firmware documentation, the option
'arm_control' has been deprecated in favor of 'arm_64bit'.
Fixes https://bugs.busybox.net/show_bug.cgi?id=11111.
Signed-off-by: Jason Tang <tang@jtang.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>