rust: turn off unsafe_op_in_unsafe_fn warning in bindgen

Currently bindgen does not provide a way to specify which
unsafe style is used.

Signed-off-by: Gary Guo <[email protected]>

Author: nbdd0121

rust/kernel/bindings.rs

@@ -9,7 +9,8 @@
     non_camel_case_types,
     non_upper_case_globals,
     non_snake_case,
-    improper_ctypes
+    improper_ctypes,
+    unsafe_op_in_unsafe_fn
 )]
 mod bindings_raw {
     use crate::c_types;