Add missing dependencies / alternatives

A number of places lacked the necessary dependencies on one of
the used features: MD, key exchange with certificate, 
entropy, or ETM.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/programs/fuzz/fuzz_privkey.c b/programs/fuzz/fuzz_privkey.c
index e8e1d44..56795d2 100644
--- a/programs/fuzz/fuzz_privkey.c
+++ b/programs/fuzz/fuzz_privkey.c
@@ -16,7 +16,7 @@
 #endif // MBEDTLS_PK_PARSE_C && MBEDTLS_CTR_DRBG_C
 
 int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
-#if defined(MBEDTLS_PK_PARSE_C) && defined(MBEDTLS_CTR_DRBG_C)
+#if defined(MBEDTLS_PK_PARSE_C) && defined(MBEDTLS_CTR_DRBG_C) && defined(MBEDTLS_ENTROPY_C)
     int ret;
     mbedtls_pk_context pk;
     mbedtls_ctr_drbg_context ctr_drbg;
@@ -88,7 +88,7 @@
 #else
     (void) Data;
     (void) Size;
-#endif // MBEDTLS_PK_PARSE_C && MBEDTLS_CTR_DRBG_C
+#endif // MBEDTLS_PK_PARSE_C && MBEDTLS_CTR_DRBG_C && MBEDTLS_ENTROPY_C
 
     return 0;
 }