Among other things, 36459f3 ([archiso] Drop aitab support, 2014-06-28)
removed the possibility to manually set a specific architecture by using
kernel parameters. This, however, is useful, e.g. when installing Arch
Linux on a device that reports itself as i586 but works fine with the
i686 flavor.
Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>