Change directory structure to align with Atmel softpack

This way we can easily check with 'diff' for differences in our code and
Atmel softpack.  Also, this layout is more suitable for building various
different firmware images (e.g. factory-test, dfu-loader, main
application) for a variety of different boards (simtrace, owhw, qmod).

firmware/libcommon/include/llist_irqsafe.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include "osmocom/core/linuxlist.h"
+
+static inline void llist_add_tail_irqsafe(struct llist_head *_new,
+					  struct llist_head *head)
+{
+	__disable_irq();
+	llist_add_tail(_new, head);
+	__enable_irq();
+}
+
+static inline struct llist_head *llist_head_dequeue_irqsafe(struct llist_head *head)
+{
+	struct llist_head *lh;
+
+	__disable_irq();
+	if (llist_empty(head)) {
+		lh = NULL;
+	} else {
+		lh = head->next;
+		llist_del(lh);
+	}
+	__enable_irq();
+
+	return lh;
+}