drivers: cache: nrf: Allow execution of sys_cache_instr_invd_all

Driver did not allow to execute any invalidate all operation.
This operation should not be allowed for data cache as it will lead to
undefined behavior but it is ok to invalidate instruction cache.

Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>

drivers/cache/cache_nrf.c

@@ -59,13 +59,6 @@ static inline void wait_for_cache(NRF_CACHE_Type *cache)
 
 static inline int _cache_all(NRF_CACHE_Type *cache, enum k_nrf_cache_op op)
 {
-	/*
-	 * We really do not want to invalidate the whole cache.
-	 */
-	if (op == K_NRF_CACHE_INVD) {
-		return -ENOTSUP;
-	}
-
 	wait_for_cache(cache);
 
 	barrier_dsync_fence_full();
@@ -218,7 +211,8 @@ void cache_data_disable(void)
 
 int cache_data_invd_all(void)
 {
-	return _cache_checks(NRF_DCACHE, K_NRF_CACHE_INVD, NULL, 0, false);
+	/* We really do not want to invalidate the whole data cache. */
+	return -ENOTSUP;
 }
 
 int cache_data_flush_and_invd_all(void)