lint: add (void) parameter to pass -Wstrict-prototypes

Note there was one place where a non-strict prototype was actually being used
with an argument, in `zmk_hog_init`. In this case, the actual argument type was
added instead.

app/include/zmk/hog.h

@@ -9,7 +9,7 @@
 #include <zmk/keys.h>
 #include <zmk/hid.h>
 
-int zmk_hog_init();
+int zmk_hog_init(const struct device *_arg);
 
 int zmk_hog_send_keyboard_report(struct zmk_hid_keyboard_report_body *body);
 int zmk_hog_send_consumer_report(struct zmk_hid_consumer_report_body *body);