Comply with mbedtls naming rules

Signed-off-by: Johan Pascal <johan.pascal@belledonne-communications.com>
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index ee2ae89..1336848 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -780,7 +780,7 @@
 static int ssl_parse_use_srtp_ext( mbedtls_ssl_context *ssl,
                                const unsigned char *buf, size_t len )
 {
-    enum mbedtls_DTLS_SRTP_protection_profiles client_protection = MBEDTLS_SRTP_UNSET_PROFILE;
+    mbedtls_dtls_srtp_protection_profiles client_protection = MBEDTLS_SRTP_UNSET_PROFILE;
     size_t i,j;
     uint16_t profile_length;