bhyve: Fix arm64 PCI I/O range to match FDT

This is supposed to combine with the memory range to make one contiguous
block, as is laid out in the FDT, so make this match what the OS is told
and thus actually configures.

Also drop the confusing leading zero from all three of these constants
that is making these 9 rather than 8 hex digits long (as one would
expect for a 32-bit address).

Reviewed by: jhb
MFC after: 2 weeks
Obtained from: CheriBSD