Pull up following revision(s) (requested by msaitoh in ticket #1327):

sys/dev/pci/piixpmreg.h: revision 1.8
sys/dev/pci/piixpm.c: revision 1.53
sys/dev/pci/piixpm.c: revision 1.54

Sync with OpenBSD's piixpm.c up to rev. 1.35:
- Print "polling" correctly when in the attach function. Same as OpenBSD
rev. 1.22-23.
- Improve debug printf()'s. Part of OpenBSD 1.24.
- Do not bus_space_map devices which are at address 0 (it's uninitialized).
  Same as OpenBSD rev. 1.25.
- Add ServerWorks HT1100 device from OpenBSD. Same as OpenBSD rev. 1.32
- Use unique wait channel. From OpenBSD rev. 1.35

Improve SB800 and newer chipsets support:
- Add newer chipset (e.g. X370/X399 and newer) support that the PCI device id
  is 0x790b. The register definitions are mainly taken from FreeBSD.
- Rename PIIXPM_INDIRECTIO_* to SB800_INDIRECTIO_* because those are only
  for SB800 and newer chipsets.
- SB800 also support 4 ports.
- SB800's interrupt configuration bit is different from others.
  Use SB800_SMB_HOSTC's bit 0.
- Do not bus_space_map devices which are at address 0 (it's uninitialized)
  in piixpm_attach().
- Add the port number to the dmesg output.
- Avoid uninitiliazed use of ctl and corresponding warnings. From OpenBSD rev.
  1.38

(martin)