PCI: unhide the SMBus on the Compaq Deskpro EN

This patch unhides the SMBus on Compaq Deskpro EN
SFF P667 with the Intel 815E chipset. Unhiding it reveals
a THMC51 hardware monitoring chip.

Jean Delvare has checked that this machine has no ACPI
magic touching the SMBus nor the hardware monitoring chip,
so this should be safe.

The patch was tested on Fedora Core 9 with 2.6.25.4 kernel.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Tested-by: Rafał Haładuda <rh1985@wp.pl>
CC: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>