3rdparty: Updated comments for Everest x25519
diff --git a/3rdparty/everest/library/x25519.c b/3rdparty/everest/library/x25519.c
index 7660b64..e5ec2e8 100644
--- a/3rdparty/everest/library/x25519.c
+++ b/3rdparty/everest/library/x25519.c
@@ -126,7 +126,8 @@
                         int( *f_rng )(void *, unsigned char *, size_t),
                         void *p_rng )
 {
-    /* CMW: Is it okay that f_rng, p_rng are not used? */
+    /* f_rng and p_rng are not used here because this implementation does not
+       need blinding since it has constant trace. */
     (( void )f_rng);
     (( void )p_rng);