init: more header cleanup

Remove includes of "log.h" that really want <android-base/logging.h>
Fix header include order
Remove headers included in .cpp files that their associated .h already includes
Remove some unused headers

Test: boot bullhead
Change-Id: I2b415adfe86a5c8bbe4fb1ebc53c7b0ee2253824
diff --git a/init/watchdogd.cpp b/init/watchdogd.cpp
index b196147..21c1e5b 100644
--- a/init/watchdogd.cpp
+++ b/init/watchdogd.cpp
@@ -16,11 +16,12 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <linux/watchdog.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
-#include <linux/watchdog.h>
+#include <android-base/logging.h>
 
 #include "log.h"
 #include "util.h"