Add special event pipes, rework ps2kb process

kernel/ipc/pipe/pipe.h

@@ -8,7 +8,8 @@
 
 #define IPC_PIPE_MAX 0x1000
 
-typedef struct {
+typedef struct IpcPipe {
+  struct IpcPipe *next;
   RBuf rbuf;
   SpinLock spinlock;
 } IpcPipe;