rust: bug: add __rust_helper to helpers

This is needed to inline these helpers into Rust code.

Reviewed-by: Boqun Feng <[email protected]>
Reviewed-by: Gary Guo <[email protected]>
Signed-off-by: Alice Ryhl <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Miguel Ojeda <[email protected]>

rust/helpers/bug.c

@@ -2,12 +2,12 @@
 
 #include <linux/bug.h>
 
-__noreturn void rust_helper_BUG(void)
+__rust_helper __noreturn void rust_helper_BUG(void)
 {
 	BUG();
 }
 
-bool rust_helper_WARN_ON(bool cond)
+__rust_helper bool rust_helper_WARN_ON(bool cond)
 {
 	return WARN_ON(cond);
 }