Fix issues when `MBEDTLS_PEM_PARSE_C` not defined

1) Fix compilatoin issues when `MBEDTLS_PEM_PARSE_C` not defined
2) remove dependency for `MBEDTLS_PEM_PARSE_C` in DER tests
diff --git a/tests/suites/test_suite_pkparse.data b/tests/suites/test_suite_pkparse.data
index b0464e5..391d6c5 100644
--- a/tests/suites/test_suite_pkparse.data
+++ b/tests/suites/test_suite_pkparse.data
@@ -107,7 +107,7 @@
 pk_parse_public_keyfile_rsa:"data_files/format_gen.pub":0
 
 Parse Public RSA Key #1 (PKCS#8 wrapped, DER)
-depends_on:MBEDTLS_MD5_C:MBEDTLS_PEM_PARSE_C
+depends_on:MBEDTLS_MD5_C
 pk_parse_public_keyfile_rsa:"data_files/rsa_pkcs8_1024_public.der":0
 
 Parse Public RSA Key #3 (PKCS#1 wrapped)
@@ -115,7 +115,7 @@
 pk_parse_public_keyfile_rsa:"data_files/rsa_pkcs1_2048_public.pem":0
 
 Parse Public RSA Key #4 (PKCS#1 wrapped, DER)
-depends_on:MBEDTLS_RSA_C:MBEDTLS_PEM_PARSE_C
+depends_on:MBEDTLS_RSA_C
 pk_parse_public_keyfile_rsa:"data_files/rsa_pkcs1_2048_public.der":0
 
 Parse Public EC Key #1 (RFC 5480, DER)