[nrf fromtree] Revert "boards: nordic: nrf54h20: disable sec ipc"

This reverts commit 5386a64.

Issue is no longer relevant. Simplify use of board by restoring
enabling secure ipc by default.

Signed-off-by: Bjarki Arge Andreasen <[email protected]>
(cherry picked from commit 89ba317a55d6a170807b1ee1d465929f1449ad61)

Author: bjarki-andreasen

boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20_cpuapp.dts

@@ -149,11 +149,16 @@
 };
 
 &cpusec_cpuapp_ipc {
+	status = "okay";
 	mbox-names = "tx", "rx";
 	tx-region = <&cpuapp_cpusec_ipc_shm>;
 	rx-region = <&cpusec_cpuapp_ipc_shm>;
 };
 
+&cpusec_bellboard {
+	status = "okay";
+};
+
 ipc0: &cpuapp_cpurad_ipc {
 	status = "okay";
 	mbox-names = "rx", "tx";

boards/nordic/nrf54h20dk/nrf54h20dk_nrf54h20_cpurad.dts

@@ -64,11 +64,16 @@
 };
 
 &cpusec_cpurad_ipc {
+	status = "okay";
 	mbox-names = "tx", "rx";
 	tx-region = <&cpurad_cpusec_ipc_shm>;
 	rx-region = <&cpusec_cpurad_ipc_shm>;
 };
 
+&cpusec_bellboard {
+	status = "okay";
+};
+
 ipc0: &cpuapp_cpurad_ipc {
 	status = "okay";
 	mbox-names = "tx", "rx";