vendor-libsecp: remove util.h patch

This patch adds a declaration of the `ecdsa_parse_compact` function to
util.h. This function isn't called from within libsecp proper; it is
called in lax_der_parse.c (which we patch separately with a declaration)
and in example code (which we don't compile at all).

secp256k1-sys/depend/secp256k1/src/util.h

@@ -8,9 +8,7 @@
 #define SECP256K1_UTIL_H
 
 #include "../include/secp256k1.h"
-extern int rustsecp256k1_v0_9_0_ecdsa_signature_parse_compact(
-        const rustsecp256k1_v0_9_0_context *ctx,
-        rustsecp256k1_v0_9_0_ecdsa_signature *sig, const unsigned char *input64);
+
 #include <stdlib.h>
 #include <stdint.h>
 #include <stdio.h>

secp256k1-sys/vendor-libsecp.sh

@@ -97,7 +97,6 @@ echo "$SOURCE_REV" >> ./secp256k1-HEAD-revision.txt
 patch "$DIR/include/secp256k1.h" "./secp256k1.h.patch"
 patch "$DIR/src/secp256k1.c" "./secp256k1.c.patch"
 patch "$DIR/src/scratch_impl.h" "./scratch_impl.h.patch"
-patch "$DIR/src/util.h" "./util.h.patch"
 
 # Fix a linking error while cross-compiling to windowns with mingw
 patch "$DIR/contrib/lax_der_parsing.c" "./lax_der_parsing.c.patch"