dm: rename device struct to udevice

using UBI and DM together leads in compiler error, as
both define a "struct device", so rename "struct device"
in include/dm/device.h to "struct udevice", as we use
linux code (MTD/UBI/UBIFS some USB code,...) and cannot
change the linux "struct device"

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Marek Vasut <marex@denx.de>
diff --git a/drivers/demo/demo-uclass.c b/drivers/demo/demo-uclass.c
index 48588be..636fd88 100644
--- a/drivers/demo/demo-uclass.c
+++ b/drivers/demo/demo-uclass.c
@@ -22,7 +22,7 @@
 	.id		= UCLASS_DEMO,
 };
 
-int demo_hello(struct device *dev, int ch)
+int demo_hello(struct udevice *dev, int ch)
 {
 	const struct demo_ops *ops = device_get_ops(dev);
 
@@ -32,7 +32,7 @@
 	return ops->hello(dev, ch);
 }
 
-int demo_status(struct device *dev, int *status)
+int demo_status(struct udevice *dev, int *status)
 {
 	const struct demo_ops *ops = device_get_ops(dev);
 
@@ -42,7 +42,7 @@
 	return ops->status(dev, status);
 }
 
-int demo_parse_dt(struct device *dev)
+int demo_parse_dt(struct udevice *dev)
 {
 	struct dm_demo_pdata *pdata = dev_get_platdata(dev);
 	int dn = dev->of_offset;