Drivers: hv: Save and export negotiated vmbus version

Export the negotiated vmbus version as this may be useful for
individual drivers.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index bee559a..134a202 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1204,5 +1204,11 @@
 void hv_kvp_deinit(void);
 void hv_kvp_onchannelcallback(void *);
 
+/*
+ * Negotiated version with the Host.
+ */
+
+extern __u32 vmbus_proto_version;
+
 #endif /* __KERNEL__ */
 #endif /* _HYPERV_H */