evl/thread: Fix duplicate included factory.h

evl/factory.h is included more than once, remove the one that isn't
necessary.
Signed-off-by: Zhang Kun <zhangkun@cdjrlc.com>

kernel/evl/thread.c

@@ -32,7 +32,6 @@
 #include <evl/thread.h>
 #include <evl/memory.h>
 #include <evl/file.h>
-#include <evl/factory.h>
 #include <evl/monitor.h>
 #include <evl/mutex.h>
 #include <evl/poll.h>