Restore ThunderX Pass1.1 PCI changes removed by r295962
If Enhanced Allocation is not used, we can't allocate any random range. All internal devices have hardcoded place where they can be located within PCI address space. Fortunately, we can read this value from BAR.
Obtained from: Semihalf
Sponsored by: Cavium
Approved by: cognet (mentor)
Reviewed by: zbb
Differential revision: https://reviews.freebsd.org/D5455