tests: remove usage of MBEDTLS_NO_PLATFORM_ENTROPY

Use MBEDTLS_PLATFORM_GET_ENTROPY_ALT instead.

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/programs/test/selftest.c b/programs/test/selftest.c
index 546716f..0941089 100644
--- a/programs/test/selftest.c
+++ b/programs/test/selftest.c
@@ -211,7 +211,7 @@
  * back.
  */
 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_ENTROPY_C)
-#if defined(MBEDTLS_ENTROPY_NV_SEED) && !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
+#if defined(MBEDTLS_ENTROPY_NV_SEED) && !defined(MBEDTLS_PLATFORM_GET_ENTROPY_ALT)
 static void create_entropy_seed_file(void)
 {
     int result;
@@ -244,7 +244,7 @@
 
 static int mbedtls_entropy_self_test_wrapper(int verbose)
 {
-#if defined(MBEDTLS_ENTROPY_NV_SEED) && !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
+#if defined(MBEDTLS_ENTROPY_NV_SEED) && !defined(MBEDTLS_PLATFORM_GET_ENTROPY_ALT)
     create_entropy_seed_file();
 #endif
     return mbedtls_entropy_self_test(verbose);