Add might_sleep() and synchronize_rcu() stubs needed by virtio_config.h.

might_sleep() is a no-op, synchronize_rcu doesn't work but we don't
need it to.

Created using Cursor CLI.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 tools/virtio/linux/kernel.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/virtio/linux/kernel.h b/tools/virtio/linux/kernel.h
index d7fc70b68a2b..416d02703f61 100644
--- a/tools/virtio/linux/kernel.h
+++ b/tools/virtio/linux/kernel.h
@@ -144,6 +144,13 @@ static inline bool is_vmalloc_addr(const void *x)
 	return false;
 }
 
+#define might_sleep() do { } while (0)
+
+static inline void synchronize_rcu(void)
+{
+	assert(0);
+}
+
 #define min(x, y) ({				\
 	typeof(x) _min1 = (x);			\
 	typeof(y) _min2 = (y);			\
-- 
MST