rust: exports: remove trailing semicolon in macro

This deals with the `checkpatch.pl` warning:

```txt
WARNING: macros should not use a trailing semicolon
+#define EXPORT_SYMBOL_RUST_GPL(sym) extern int sym; EXPORT_SYMBOL_GPL(sym);
```

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Author: ojeda

rust/exports.c

@@ -13,7 +13,7 @@
 
 #include <linux/module.h>
 
-#define EXPORT_SYMBOL_RUST_GPL(sym) extern int sym; EXPORT_SYMBOL_GPL(sym);
+#define EXPORT_SYMBOL_RUST_GPL(sym) extern int sym; EXPORT_SYMBOL_GPL(sym)
 
 #include "exports_core_generated.h"
 #include "exports_alloc_generated.h"