build: LOG_TAG consistency, include order, build fixes

Fix the order of includes across a bunch of files, and declare LOG_TAG
at the top of every file in which it is used.

Consistently use bt_ as a LOG_TAG prefix.
Fix issues with LOG macro usage.
Remove unused includes and double-includes (when in related .h)

Add includes as necessary to compile cleanly (problems surfaced by
reordering includes)

Change-Id: Ic55520c8302b06bbc1942c10c448b20844669da6
diff --git a/osi/include/fixed_queue.h b/osi/include/fixed_queue.h
index 5c32ac7..52862bf 100644
--- a/osi/include/fixed_queue.h
+++ b/osi/include/fixed_queue.h
@@ -19,6 +19,7 @@
 #pragma once
 
 #include <stdbool.h>
+#include <stdlib.h>
 
 struct fixed_queue_t;
 typedef struct fixed_queue_t fixed_queue_t;