viafb: Turn GPIO and i2c into proper platform devices

Another step toward making this thing a real multifunction device driver.

Cc: ScottFang@viatech.com.cn
Cc: JosephChan@via.com.tw
Cc: Harald Welte <laforge@gnumonks.org>
Acked-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/drivers/video/via/via-core.h b/drivers/video/via/via-core.h
index d004290..ac89c2a 100644
--- a/drivers/video/via/via-core.h
+++ b/drivers/video/via/via-core.h
@@ -63,6 +63,7 @@
 struct viafb_dev {
 	struct pci_dev *pdev;
 	int chip_type;
+	struct via_port_cfg *port_cfg;
 	/*
 	 * Spinlock for access to device registers.  Not yet
 	 * globally used.