Enable automatic superpages promotion by default on ARMv6/v7

From now on superpages are enabled by default on ARM.
One can still disable superpages utilization by adding:

vm.pmap.sp_enabled=0

to loader.conf
Add libvmmapi functions vm_copyin() and vm_copyout() to copy into and out
of the guest linear address space. These APIs in turn use a new ioctl
'VM_GLA2GPA' to convert the guest linear address to guest physical.

Use the new copyin/copyout APIs when emulating ins/outs instruction in
bhyve(8).