overlays: Give a deprecation warning for dwc-otg

The overlay deprecation feature does not give any advance warnings,
just a more user-friendly error message; it's more termination than
deprecation.

Abuse the overlay rename feature to cause a warning message to be
displayed when dwc-otg is loaded:

  dtwarn: overlay 'dwc-otg' has been renamed 'dwc-otg-deprecated'

Signed-off-by: Phil Elwell <[email protected]>

Author: pelwell

arch/arm/boot/dts/overlays/Makefile

@@ -60,7 +60,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
 	dpi18cpadhi.dtbo \
 	dpi24.dtbo \
 	draws.dtbo \
-	dwc-otg.dtbo \
+	dwc-otg-deprecated.dtbo \
 	dwc2.dtbo \
 	edt-ft5406.dtbo \
 	enc28j60.dtbo \

arch/arm/boot/dts/overlays/README

@@ -1246,10 +1246,13 @@ Params: draws_adc_ch4_gain      Sets the full scale resolution of the ADCs
 
 
 Name:   dwc-otg
-Info:   Selects the dwc_otg USB controller driver which has fiq support. This
-        is the default on all except the Pi Zero which defaults to dwc2.
-Load:   dtoverlay=dwc-otg
-Params: <None>
+Info:   The dwc-otg has been deprecated.
+Load:   <Deprecated>
+
+
+Name:   dwc-otg-deprecated
+Info:   The dwc-otg has been deprecated.
+Load:   <Deprecated>
 
 
 Name:   dwc2

arch/arm/boot/dts/overlays/dwc-otg-overlay.dts renamed to arch/arm/boot/dts/overlays/dwc-otg-deprecated-overlay.dts

@@ -53,6 +53,10 @@
 		bcm2712;
 	};
 
+	dwc-otg {
+		renamed = "dwc-otg-deprecated";
+	};
+
 	hifiberry-adc8x {
 		bcm2712;
 	};