kernel: add closing comments to config endifs

Add a closing comment to the endif with the configuration
information to which the endif belongs too.
To make the code more clearer if the configs need adaptions.

Signed-off-by: Simon Hein <Shein@baumer.com>

kernel/timer.c

diff --git a/kernel/timer.c b/kernel/timer.c
index 48cc69b..8eafbb4 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -17,7 +17,7 @@
 
 #ifdef CONFIG_OBJ_CORE_TIMER
 static struct k_obj_type obj_type_timer;
-#endif
+#endif /* CONFIG_OBJ_CORE_TIMER */
 
 /**
  * @brief Handle expiration of a kernel timer object.
@@ -72,7 +72,7 @@
 		 * down" behavior on timeout addition).
 		 */
 		next = K_TIMEOUT_ABS_TICKS(k_uptime_ticks() + 1 + next.ticks);
-#endif
+#endif /* CONFIG_TIMEOUT_64BIT */
 		z_add_timeout(&timer->timeout, z_timer_expiration_handler,
 			      next);
 	}
@@ -132,7 +132,7 @@
 
 #ifdef CONFIG_OBJ_CORE_TIMER
 	k_obj_core_init_and_link(K_OBJ_CORE(timer), &obj_type_timer);
-#endif
+#endif /* CONFIG_OBJ_CORE_TIMER */
 }
 
 
@@ -189,7 +189,7 @@
 	z_impl_k_timer_start(timer, duration, period);
 }
 #include <syscalls/k_timer_start_mrsh.c>
-#endif
+#endif /* CONFIG_USERSPACE */
 
 void z_impl_k_timer_stop(struct k_timer *timer)
 {
@@ -222,7 +222,7 @@
 	z_impl_k_timer_stop(timer);
 }
 #include <syscalls/k_timer_stop_mrsh.c>
-#endif
+#endif /* CONFIG_USERSPACE */
 
 uint32_t z_impl_k_timer_status_get(struct k_timer *timer)
 {
@@ -242,7 +242,7 @@
 	return z_impl_k_timer_status_get(timer);
 }
 #include <syscalls/k_timer_status_get_mrsh.c>
-#endif
+#endif /* CONFIG_USERSPACE */
 
 uint32_t z_impl_k_timer_status_sync(struct k_timer *timer)
 {
@@ -342,7 +342,7 @@
 }
 #include <syscalls/k_timer_user_data_set_mrsh.c>
 
-#endif
+#endif /* CONFIG_USERSPACE */
 
 #ifdef CONFIG_OBJ_CORE_TIMER
 static int init_timer_obj_core_list(void)
@@ -362,4 +362,4 @@
 }
 SYS_INIT(init_timer_obj_core_list, PRE_KERNEL_1,
 	 CONFIG_KERNEL_INIT_PRIORITY_OBJECTS);
-#endif
+#endif /* CONFIG_OBJ_CORE_TIMER */