snippets: sdp: mspi: Add fault timer node

Add a fault timer node to be used as a watchdog timer
for the SDP MSPI FLPR application.

Signed-off-by: Jakub Zymelka <jakub.zymelka@nordicsemi.no>

Author: jaz1-nordic

snippets/sdp/mspi/sdp-mspi-app.overlay

@@ -13,3 +13,9 @@
 		#size-cells = <0>;
 	};
 };
+
+/* TIMER peripheral as a watchdog for SDP FW */
+fault_timer: &timer20 {
+	status = "okay";
+	prescaler = <4>;
+};