Use red-black trees to store process run queue and process list

kernel/amd64/smp.h

@@ -4,6 +4,7 @@
 #include <amd64/gdt.h>
 #include <amd64/tss.h>
 #include <aux/compiler.h>
+#include <libk/rbtree.h>
 #include <libk/std.h>
 #include <proc/proc.h>
 
@@ -30,9 +31,9 @@ struct cpu {
 
   spin_lock_t lock;
 
-  struct proc* proc_run_q;
+  struct rb_node_link* proc_run_q;
   struct proc* proc_current;
-} PACKED;
+};
 
 struct cpu* cpu_make (void);
 struct cpu* cpu_get (void);