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/spi/mpc52xx_spi.c b/drivers/spi/mpc52xx_spi.c
index 56136ff..ec9f0b1 100644
--- a/drivers/spi/mpc52xx_spi.c
+++ b/drivers/spi/mpc52xx_spi.c
@@ -390,7 +390,7 @@
 /*
  * OF Platform Bus Binding
  */
-static int __devinit mpc52xx_spi_probe(struct of_device *op,
+static int __devinit mpc52xx_spi_probe(struct platform_device *op,
 				       const struct of_device_id *match)
 {
 	struct spi_master *master;
@@ -530,7 +530,7 @@
 	return rc;
 }
 
-static int __devexit mpc52xx_spi_remove(struct of_device *op)
+static int __devexit mpc52xx_spi_remove(struct platform_device *op)
 {
 	struct spi_master *master = dev_get_drvdata(&op->dev);
 	struct mpc52xx_spi *ms = spi_master_get_devdata(master);