Fix filename in comment.

util-64.c was renamed.

Change-Id: I825b1ebe3e3f428e883ed72b51d50c6bf6ab69f7
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/36226
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>

crypto/fipsmodule/ec/p256-x86_64.c

diff --git a/crypto/fipsmodule/ec/p256-x86_64.c b/crypto/fipsmodule/ec/p256-x86_64.c
index d63e998..b4af544 100644
--- a/crypto/fipsmodule/ec/p256-x86_64.c
+++ b/crypto/fipsmodule/ec/p256-x86_64.c
@@ -48,7 +48,8 @@
 // Precomputed tables for the default generator
 #include "p256-x86_64-table.h"
 
-// Recode window to a signed digit, see util-64.c for details
+// Recode window to a signed digit, see |ec_GFp_nistp_recode_scalar_bits| in
+// util.c for details
 static unsigned booth_recode_w5(unsigned in) {
   unsigned s, d;