Staging: hv: channel: export vmbus_sendpacket_pagebuffer to modules

Drivers need to call this directly, so export it, like other
vmbus functions.

Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/hv/channel.c

@@ -823,6 +823,7 @@ int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 
 /*
  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet