rust: exclude DETECT_BYTEMATH_ENDIAN_DEFAULT from bindings

to deal with the failure due to cbindgen updates and mismatches in
generated bindings.

detect-bytemath.c:61: error: "DETECT_BYTEMATH_ENDIAN_DEFAULT" redefined [-Werror]
   61 | #define DETECT_BYTEMATH_ENDIAN_DEFAULT (uint8_t) BigEndian
      |
In file included from rust.h:34,
                 from detect-bytemath.c:32:
./../rust/gen/rust-bindings.h:5071: note: this is the location of the previous definition
 5071 | #define DETECT_BYTEMATH_ENDIAN_DEFAULT BigEndian
      |

rust/cbindgen.toml

@@ -86,6 +86,7 @@ include = [
 # default: []
 exclude = [
     "CLuaState",
+    "DETECT_BYTEMATH_ENDIAN_DEFAULT",
 ]
 
 # Types of items that we'll generate. If empty, then all types of item are emitted.