of/device: Replace struct of_device with struct platform_device

of_device is just an alias for platform_device, so remove it entirely.  Also
replace to_of_device() with to_platform_device() and update comment blocks.

This patch was initially generated from the following semantic patch, and then
edited by hand to pick up the bits that coccinelle didn't catch.

@@
@@
-struct of_device
+struct platform_device

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Reviewed-by: David S. Miller <davem@davemloft.net>

drivers/video/ffb.c

@@ -893,7 +893,7 @@ static void ffb_init_fix(struct fb_info *info)
 	info->fix.accel = FB_ACCEL_SUN_CREATOR;
 }
 
-static int __devinit ffb_probe(struct of_device *op,
+static int __devinit ffb_probe(struct platform_device *op,
 			       const struct of_device_id *match)
 {
 	struct device_node *dp = op->dev.of_node;
@@ -1023,7 +1023,7 @@ out_err:
 	return err;
 }
 
-static int __devexit ffb_remove(struct of_device *op)
+static int __devexit ffb_remove(struct platform_device *op)
 {
 	struct fb_info *info = dev_get_drvdata(&op->dev);
 	struct ffb_par *par = info->par;