Rewrite PS2KB using the new devctl interface

kernel/kmain.c

@@ -12,6 +12,7 @@
 #include "util/util.h"
 #include "proc/proc.h"
 #include "dev/termdev.h"
+#include "dev/ps2kbdev.h"
 
 const char *human_size(uint64_t bytes, char *buf, size_t bufsize) {
   static const char *units[] = { "B", "KiB", "MiB", "GiB", "TiB", "PiB" };
@@ -66,6 +67,7 @@ void kmain(void) {
   baseimg_init();
   vfs_init();
   termdev_init();
+  ps2kbdev_init();
   proc_init();
 
   for(;;);