kernel: add equeue object

equeue is a way for the kernel to deliver events to userspace programs.

kernel/equeue.c

@@ -0,0 +1,29 @@
+#include <kernel/equeue.h>
+
+kern_status_t equeue_type_init(void)
+{
+	return KERN_UNIMPLEMENTED;
+}
+
+struct equeue *equeue_cast(struct object *obj)
+{
+	return NULL;
+}
+
+struct equeue *equeue_create(void)
+{
+	return NULL;
+}
+
+kern_status_t equeue_enqueue(
+	struct equeue *q,
+	const equeue_packet_t *pkt,
+	enum equeue_flags flags)
+{
+	return KERN_UNIMPLEMENTED;
+}
+
+kern_status_t equeue_dequeue(struct equeue *q, equeue_packet_t *out)
+{
+	return KERN_UNIMPLEMENTED;
+}