Guard mbedtls_pkcs5_pbes2() by MBEDTLS_ASN1_PARSE_C

Previously, mbedtls_pkcs5_pbes2() was unconditionally declared
in `pkcs5.h` but defined as a stub returning
`MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE` in case
MBEDTLS_ASN1_PARSE_C was not defined.

In line with the previous commits, this commit removes declaration
and definition from both `pkcs5.h` and `pkcs5.c` in case
MBEDTLS_ASN1_PARSE_C is not defined.

Author: Hanno Becker

include/mbedtls/pkcs5.h

@@ -44,6 +44,8 @@
 extern "C" {
 #endif
 
+#if defined(MBEDTLS_ASN1_PARSE_C)
+
 /**
  * \brief          PKCS#5 PBES2 function
  *
@@ -62,6 +64,8 @@ int mbedtls_pkcs5_pbes2( const mbedtls_asn1_buf *pbe_params, int mode,
                  const unsigned char *data, size_t datalen,
                  unsigned char *output );
 
+#endif /* MBEDTLS_ASN1_PARSE_C */
+
 /**
  * \brief          PKCS#5 PBKDF2 using HMAC
  *

library/pkcs5.c

@@ -54,22 +54,7 @@
 #define mbedtls_printf printf
 #endif
 
-#if !defined(MBEDTLS_ASN1_PARSE_C)
-int mbedtls_pkcs5_pbes2( const mbedtls_asn1_buf *pbe_params, int mode,
-                 const unsigned char *pwd,  size_t pwdlen,
-                 const unsigned char *data, size_t datalen,
-                 unsigned char *output )
-{
-    ((void) pbe_params);
-    ((void) mode);
-    ((void) pwd);
-    ((void) pwdlen);
-    ((void) data);
-    ((void) datalen);
-    ((void) output);
-    return( MBEDTLS_ERR_PKCS5_FEATURE_UNAVAILABLE );
-}
-#else
+#if defined(MBEDTLS_ASN1_PARSE_C)
 static int pkcs5_parse_pbkdf2_params( const mbedtls_asn1_buf *params,
                                       mbedtls_asn1_buf *salt, int *iterations,
                                       int *keylen, mbedtls_md_type_t *md_type )