Add error condition for bad user configurations

This commit adds an error condition for bad user configurations
and updates the number of SSL module errors in error.h.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 7fec65e..ce95cec 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -129,6 +129,7 @@
 #define MBEDTLS_ERR_SSL_UNEXPECTED_CID                    -0x6000  /**< An encrypted DTLS-frame with an unexpected CID was received. */
 #define MBEDTLS_ERR_SSL_VERSION_MISMATCH                  -0x5F00  /**< An operation failed due to an unexpected version or configuration. */
 #define MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS                -0x7000  /**< A cryptographic operation is in progress. Try again later. */
+#define MBEDTLS_ERR_SSL_BAD_CONFIG                        -0x5E80  /**< Invalid value in SSL config */
 
 /*
  * Various constants