kernel: fix -Wstrict-prototypes warnings/errors

* On newer kernel for some reason -Wno-strict-prototypes still does not fix the errors or warnings.
* To fix it, we just need to add void type.

Signed-off-by: rsuntk <rsuntk@yukiprjkt.my.id>

kernel/selinux/selinux.h

@@ -15,12 +15,12 @@ void setenforce(bool);
 
 bool getenforce(void);
 
-bool is_ksu_domain();
+bool is_ksu_domain(void);
 
 bool is_zygote(void *cred);
 
-void apply_kernelsu_rules();
+void apply_kernelsu_rules(void);
 
-u32 ksu_get_devpts_sid();
+u32 ksu_get_devpts_sid(void);
 
 #endif