| host arch | arm64 | armhf | armel |
-------------------------------------
| arm64     |   X   |   X   |   X   |
| armhf     |       |   X   |   X   |
| armel     |       |   X   |   X   |
-------------------------------------

Although optional, all existing arm64 silicon supports 32bit instructions.
armel/armhf is only a userspace change, so they are interchangeable.
However armhf isn't supported on all armel platforms (e.g. armv6) but
all those we support have hard-float.
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>