tests: benchmark: kernel_freq_change: Remove NIOS2 reference

Removes a refernce to an architecture that has been removed from
zephyr. Also fixes the wrong license of this file which should
have been licensed the way it was

Signed-off-by: Jamie McCrae <[email protected]>

Author: nordicjm

scripts/ci/license_allow_list.yaml

@@ -47,6 +47,7 @@ Apache-2.0: |
   ^nrf/modules/trusted-firmware-m/fault.c
   ^nrf/modules/openthread/
   ^nrf/samples/net/http_server/src/main.c
+  ^nrf/tests/benchmarks/kernel_freq_change/src/kernel_context.c
   ^nrf/tests/subsys/suit/common/tls_config/user-tls-conf.h
   ^nrf/subsys/settings/
   ^nrf/tests/zephyr/subsys/settings/

tests/benchmarks/kernel_freq_change/src/kernel_context.c

@@ -1,7 +1,8 @@
 /*
+ * Copyright (c) 2012-2015 Wind River Systems, Inc.
  * Copyright (c) 2025 Nordic Semiconductor ASA
  *
- * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ * SPDX-License-Identifier: Apache-2.0
  */
 
 #include <zephyr/kernel.h>
@@ -49,13 +50,10 @@ static void busy_wait_thread(void *mseconds, void *arg2, void *arg3)
 
 	k_busy_wait(usecs);
 
-	/* FIXME: Broken on Nios II, see #22956 */
-#ifndef CONFIG_NIOS2
 	int key = arch_irq_lock();
 
 	k_busy_wait(usecs);
 	arch_irq_unlock(key);
-#endif
 
 	/*
 	 * Ideally the test should verify that the correct number of ticks