drm/i915: Change I2C api to pass around i2c_adapters

The existing API passed around intel_i2c_chan pointers, which are dependent
on the i2c bit-banging algo. This precluded the driver from using outputs
which use a different algo. Switching to the more general i2c_adpater allows
the driver to support non bit-banging DDC.

This also required moving the slave address into the output private
structures.

Signed-off-by: Keith Packard <keithp@keithp.com>
diff --git a/drivers/gpu/drm/i915/intel_dvo.c b/drivers/gpu/drm/i915/intel_dvo.c
index 1ee3007..13bff20 100644
--- a/drivers/gpu/drm/i915/intel_dvo.c
+++ b/drivers/gpu/drm/i915/intel_dvo.c
@@ -384,10 +384,9 @@
 {
 	struct intel_output *intel_output;
 	struct intel_dvo_device *dvo;
-	struct intel_i2c_chan *i2cbus = NULL;
+	struct i2c_adapter *i2cbus = NULL;
 	int ret = 0;
 	int i;
-	int gpio_inited = 0;
 	int encoder_type = DRM_MODE_ENCODER_NONE;
 	intel_output = kzalloc (sizeof(struct intel_output), GFP_KERNEL);
 	if (!intel_output)
@@ -420,14 +419,11 @@
 		 * It appears that everything is on GPIOE except for panels
 		 * on i830 laptops, which are on GPIOB (DVOA).
 		 */
-		if (gpio_inited != gpio) {
-			if (i2cbus != NULL)
-				intel_i2c_destroy(i2cbus);
-			if (!(i2cbus = intel_i2c_create(dev, gpio,
-				gpio == GPIOB ? "DVOI2C_B" : "DVOI2C_E"))) {
-				continue;
-			}
-			gpio_inited = gpio;
+		if (i2cbus != NULL)
+			intel_i2c_destroy(i2cbus);
+		if (!(i2cbus = intel_i2c_create(dev, gpio,
+			gpio == GPIOB ? "DVOI2C_B" : "DVOI2C_E"))) {
+			continue;
 		}
 
 		if (dvo->dev_ops!= NULL)