viafb: fix PCI table

This patch fixes an oddity in the device table where the P4M890 ID was
assigned with the enumeration value of CN700 which itself was missing.
This is a regression introduced by
	"viafb: make viafb a first-class citizen using pci_driver"

While at it reorder the table to reflect the order of the  enumeration
values.
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Joseph Chan <JosephChan@via.com.tw>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Harald Welte <laforge@gnumonks.org>