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>
diff --git a/drivers/sbus/char/envctrl.c b/drivers/sbus/char/envctrl.c
index 3c27f45..078e5f4 100644
--- a/drivers/sbus/char/envctrl.c
+++ b/drivers/sbus/char/envctrl.c
@@ -1027,7 +1027,7 @@
 	return 0;
 }
 
-static int __devinit envctrl_probe(struct of_device *op,
+static int __devinit envctrl_probe(struct platform_device *op,
 				   const struct of_device_id *match)
 {
 	struct device_node *dp;
@@ -1104,7 +1104,7 @@
 	return err;
 }
 
-static int __devexit envctrl_remove(struct of_device *op)
+static int __devexit envctrl_remove(struct platform_device *op)
 {
 	int index;