From: Arnd Bergmann <arnd@xxxxxxxx>
When CONFIG_MODULE_UNLOAD is disabled, the module->exit member
is not defined, causing a build failure:
kernel/module.c:4493:8: error: no member named 'exit' in 'struct module'
mod->exit = *exit;
add an #ifdef block around this.
Fixes: cf68fffb66d6 ("add support for Clang CFI")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>