Remove redundant minimum length check

Availability of sufficient incoming data should be checked when
it is needed, which is in mbedtls_ssl_fetch_input(), and this
function has the necessary bounds checks in place.
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 5eed60b..1aeadbd 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -4879,17 +4879,6 @@
     }
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
-
-    /* Check length against bounds of the current transform and version */
-    if( ssl->transform_in != NULL )
-    {
-        if( ssl->in_msglen < ssl->transform_in->minlen )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) );
-            return( MBEDTLS_ERR_SSL_INVALID_RECORD );
-        }
-    }
-
     return( 0 );
 }