migration: Move migration.h to migration/

Nothing uses it outside of migration.h

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
diff --git a/migration/channel.c b/migration/channel.c
index 92f6f99..3b7252f 100644
--- a/migration/channel.c
+++ b/migration/channel.c
@@ -13,7 +13,7 @@
 #include "qemu/osdep.h"
 #include "channel.h"
 #include "tls.h"
-#include "migration/migration.h"
+#include "migration.h"
 #include "qemu-file-channel.h"
 #include "trace.h"
 #include "qapi/error.h"