mshv: release mutex on region invalidation failure

mshv: release mutex on region invalidation failure

In the region invalidation failure path in
mshv_region_interval_invalidate(), the region mutex is not released. Fix
it by releasing the mutex in the failure path.

Signed-off-by: Anirudh Rayabharam (Microsoft) <anirudh@anirudhrb.com>
Fixes: b9a66cd5ccbb ("mshv: Add support for movable memory regions")
Acked-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Reviewed-by: Roman Kisel <vdso@mailbox.org>
Signed-off-by: Wei Liu <wei.liu@kernel.org>