powerpc: 86xx: Rename wdt@ nodes to watchdog@

The watchdog.yaml schema prescribes a node name of "timer" or "watchdog"
rather than the abbreviation "wdt".

Signed-off-by: J. Neuschäfer <[e-mail]>
Reviewed-by: Christophe Leroy <[e-mail]>
Signed-off-by: Madhavan Srinivasan <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

arch/powerpc/boot/dts/fsl/gef_ppc9a.dts

···
 			reg = <0x4 0x0 0x40>;
 		};
 
-		wdt@4,2000 {
+		watchdog@4,2000 {
 			compatible = "gef,ppc9a-fpga-wdt", "gef,fpga-wdt-1.00",
 				"gef,fpga-wdt";
 			reg = <0x4 0x2000 0x8>;
···
 			interrupt-parent = <&gef_pic>;
 		};
 		/* Second watchdog available, driver currently supports one.
-		wdt@4,2010 {
+		watchdog@4,2010 {
 			compatible = "gef,ppc9a-fpga-wdt", "gef,fpga-wdt-1.00",
 				"gef,fpga-wdt";
 			reg = <0x4 0x2010 0x8>;

arch/powerpc/boot/dts/fsl/gef_sbc310.dts

···
 			reg = <0x4 0x0 0x40>;
 		};
 
-		wdt@4,2000 {
+		watchdog@4,2000 {
 			compatible = "gef,sbc310-fpga-wdt", "gef,fpga-wdt-1.00",
 				"gef,fpga-wdt";
 			reg = <0x4 0x2000 0x8>;
···
 			interrupt-parent = <&gef_pic>;
 		};
 /*
-		wdt@4,2010 {
+		watchdog@4,2010 {
 			compatible = "gef,sbc310-fpga-wdt", "gef,fpga-wdt-1.00",
 				"gef,fpga-wdt";
 			reg = <0x4 0x2010 0x8>;

arch/powerpc/boot/dts/fsl/gef_sbc610.dts

···
 			reg = <0x4 0x0 0x40>;
 		};
 
-		wdt@4,2000 {
+		watchdog@4,2000 {
 			compatible = "gef,fpga-wdt";
 			reg = <0x4 0x2000 0x8>;
 			interrupts = <0x1a 0x4>;
 			interrupt-parent = <&gef_pic>;
 		};
 		/* Second watchdog available, driver currently supports one.
-		wdt@4,2010 {
+		watchdog@4,2010 {
 			compatible = "gef,fpga-wdt";
 			reg = <0x4 0x2010 0x8>;
 			interrupts = <0x1b 0x4>;