migration: do not include coroutine_int.h

Migration code needs no private fields of the coroutine backend.
Include the "regular" coroutine.h header.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/migration/migration.h b/migration/migration.h
index 8045e39..6c612c0 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -19,7 +19,7 @@
 #include "qapi/qapi-types-migration.h"
 #include "qapi/qmp/json-writer.h"
 #include "qemu/thread.h"
-#include "qemu/coroutine_int.h"
+#include "qemu/coroutine.h"
 #include "io/channel.h"
 #include "io/channel-buffer.h"
 #include "net/announce.h"