[nrf fromtree] tests: boards: nrf: i2c: i2c_slave: Run test on nrf54l15 NS

Enable i2c_slave test on nrf54l15dk/nrf54l15/cpuapp/ns platform.

Signed-off-by: Sebastian Głąb <[email protected]>
(cherry picked from commit 55f9d2c)

Author: nordic-segl

tests/boards/nrf/i2c/i2c_slave/boards/nrf54l15dk_nrf54l15_cpuapp_ns.conf

@@ -0,0 +1 @@
+CONFIG_NRFX_TWIS22=y

tests/boards/nrf/i2c/i2c_slave/boards/nrf54l15dk_nrf54l15_cpuapp_ns.overlay

@@ -0,0 +1,7 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "nrf54l15dk_nrf54l15_cpuapp.overlay"

tests/boards/nrf/i2c/i2c_slave/testcase.yaml

@@ -15,6 +15,7 @@ tests:
       - nrf54h20dk/nrf54h20/cpuapp
       - nrf54h20dk/nrf54h20/cpuppr
       - nrf54l15dk/nrf54l15/cpuapp
+      - nrf54l15dk/nrf54l15/cpuapp/ns
       - nrf54lm20dk/nrf54lm20a/cpuapp
     integration_platforms:
       - nrf52840dk/nrf52840
@@ -30,6 +31,7 @@ tests:
       - nrf54h20dk/nrf54h20/cpuapp
       - nrf54h20dk/nrf54h20/cpuppr
       - nrf54l15dk/nrf54l15/cpuapp
+      - nrf54l15dk/nrf54l15/cpuapp/ns
       - nrf54lm20dk/nrf54lm20a/cpuapp
     integration_platforms:
       - nrf52840dk/nrf52840