s3fb: add DDC support

Add I2C support for the DDC bus and also default mode initialization by
reading monitor EDID to the s3fb driver.

Tested on Trio64V+ (2 cards), Trio64V2/DX, Virge (3 cards),
Virge/DX (3 cards), Virge/GX2, Trio3D/2X (4 cards), Trio3D.

Will probably not work on Trio32 - my 2 cards have DDC support in BIOS that
looks different from the other cards but the DDC pins on the VGA connector
are not connected.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index e6a8d8c..e2126b5 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -1463,6 +1463,14 @@
 	---help---
 	  Driver for graphics boards with S3 Trio / S3 Virge chip.
 
+config FB_S3_DDC
+	bool "DDC for S3 support"
+	depends on FB_S3
+	select FB_DDC
+	default y
+	help
+	  Say Y here if you want DDC support for your S3 graphics card.
+
 config FB_SAVAGE
 	tristate "S3 Savage support"
 	depends on FB && PCI && EXPERIMENTAL