chore: Update code coverage on x86_64

After merging `kvm-bindings` and `kvm-ioctls`, the code coverage has
changed, update coverage of `coverage_config_x86_64.json` to 91.46 as
suggested by coverage test.

Signed-off-by: Ruoqing He <heruoqing@iscas.ac.cn>

coverage_config_x86_64.json

@@ -1,5 +1,5 @@
 {
-  "coverage_score": 79.17,
+  "coverage_score": 91.46,
   "exclude_path": ".*bindings\\.rs",
   "crate_features": "fam-wrappers,serde"
 }