Add support for every single SiS chipset out there

The two existing SiS chipset enables (compared to the 28 in this patch)
were refactored, and one of them was fixed.

A function to match PCI vendor/class combinations was added to generic
code.

Tested on the "Elitegroup K7S5A". Results are somewhat unexpected (some
PCI settings seem to be inaccessible, but it still works).

This is not based on any docs, but rather on detailed analysis
of existing opensource code for some of the chipsets.

Thanks to for Adrian Glaubitz testing.

Corresponding to flashrom svn r759.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
diff --git a/flash.h b/flash.h
index 4d15816..d245824 100644
--- a/flash.h
+++ b/flash.h
@@ -389,6 +389,7 @@
 
 /* internal.c */
 struct pci_dev *pci_dev_find_filter(struct pci_filter filter);
+struct pci_dev *pci_dev_find_vendorclass(uint16_t vendor, uint16_t class);
 struct pci_dev *pci_dev_find(uint16_t vendor, uint16_t device);
 struct pci_dev *pci_card_find(uint16_t vendor, uint16_t device,
 			      uint16_t card_vendor, uint16_t card_device);