Update opensbi submodule to upstream master

Updating from commit id ce228ee:
2019-07-02 11:11:08 +0530 - (include: Bump-up version to 0.4)

to commit id e561c63:
2019-10-02 17:03:58 +0530 - (lib: Fix coldboot race condition observed on emulators/simulators)

This brings in 44 new commits.

Change-Id: Ide6e3c2bb98e79750b40a9b8ca9f2f1d2c123628
Signed-off-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35314
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

3rdparty/opensbi

@@ -1 +1 @@
-Subproject commit ce228ee0919deb9957192d723eecc8aaae2697c6
+Subproject commit e561c6303639ed510183da25d3d54555a53371c9