mosh: don't show dependencies comment on unsupported arches

Cc: Christian Stewart <christian@paral.in>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Acked-by: "Christian Stewart" <c <yann.morin.1998@free.fr>hristian@paral.in>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>