Implement static_assert! in a more idiomatic way

Author: alex

rust/kernel/static_assert.rs

@@ -29,10 +29,6 @@
 #[macro_export]
 macro_rules! static_assert {
     ($condition:expr) => {
-        // Based on the latest one in `rustc`'s one before it was [removed].
-        //
-        // [removed]: https://github.com/rust-lang/rust/commit/c2dad1c6b9f9636198d7c561b47a2974f5103f6d
-        #[allow(dead_code)]
-        const _: () = [()][!($condition) as usize];
+        const _: () = assert!($condition);
     };
 }