Go way past 11 and bump bhyve's max vCPUs to 16.

This should be sufficient for 10.0 and will do
until forthcoming work to avoid limitations
in this area is complete.

Thanks to Bela Lubkin at tidalscale for the
headsup on the apic/cpu id/io apic ASL parameters
that are actually hex values and broke when
written as decimal when 11 vCPUs were configured.

Approved by:	re@