tests: drivers: gpio: gpio_more_loops: Enable test on 54L* cpuflpr

Add overlay files required to run the test on the FLPR core of
nRF54L15, nRF54L09, nRF54L20.

Signed-off-by: Sebastian Głąb <sebastian.glab@nordicsemi.no>

Author: nordic-segl

tests/drivers/gpio/gpio_more_loops/boards/nrf54l09pdk_nrf54l09_cpuflpr.overlay

@@ -0,0 +1,7 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+#include "nrf54l09pdk_nrf54l09_cpuapp.overlay"

tests/drivers/gpio/gpio_more_loops/boards/nrf54l15dk_nrf54l15_cpuflpr.overlay

@@ -0,0 +1,7 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+#include "nrf54l15dk_nrf54l15_cpuapp.overlay"

tests/drivers/gpio/gpio_more_loops/boards/nrf54l20pdk_nrf54l20_cpuflpr.overlay

@@ -0,0 +1,7 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+#include "nrf54l20pdk_nrf54l20_cpuapp.overlay"

tests/drivers/gpio/gpio_more_loops/testcase.yaml

@@ -13,8 +13,11 @@ tests:
   drivers.gpio.gpio_more_loops:
     platform_allow:
       - nrf54l15dk/nrf54l15/cpuapp
-      - nrf54l20pdk/nrf54l20/cpuapp
+      - nrf54l15dk/nrf54l15/cpuflpr
       - nrf54l09pdk/nrf54l09/cpuapp
+      - nrf54l09pdk/nrf54l09/cpuflpr
+      - nrf54l20pdk/nrf54l20/cpuapp
+      - nrf54l20pdk/nrf54l20/cpuflpr
       - nrf54h20dk/nrf54h20/cpuapp
     integration_platforms:
       - nrf54l15dk/nrf54l15/cpuapp