oid.h: remove redundant MBEDTLS_MD_C dependency

Signed-off-by: Przemek Stekiel <przemyslaw.stekiel@mobica.com>
diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index a3fafae..a36a20f 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -519,7 +519,6 @@
                            const char **oid, size_t *olen );
 #endif /* MBEDTLS_ECP_C */
 
-#if defined(MBEDTLS_MD_C)
 /**
  * \brief          Translate SignatureAlgorithm OID into md_type and pk_type
  *
@@ -564,7 +563,6 @@
  * \return         0 if successful, or MBEDTLS_ERR_OID_NOT_FOUND
  */
 int mbedtls_oid_get_md_hmac( const mbedtls_asn1_buf *oid, mbedtls_md_type_t *md_hmac );
-#endif /* MBEDTLS_MD_C */
 
 /**
  * \brief          Translate hash algorithm OID into md_type