definitions from ppbreg.h and move some definitions from ppbreg.h to
pcireg.h.
- Change fast back-to-back "capable" to "enable" in pci_subr.c.
- Print Primary Discard Timer, Secondary Discard Timer, Discard Timer Status
and Discard Timer SERR# Enable bit in pci_subr.c.
- PCI_BRIDGE_PREFETCHBASE32_REG and PCI_BRIDGE_PREFETCHLIMIT32_REG are
"upper" 32bit registers, rename to *UP32_REG to avoid confusion.
- Use macro.