Drivers: hv: vmbus: Change server monitor_pages index to 0

Change the monitor_pages index in server_monitor_pending_show() to '0'.
'0' is the correct monitor_pages index for the server. A comment for the
monitor_pages field in the vmbus_connection struct definition indicates
that the 1st page is for parent->child notifications. In addition, the
server_monitor_latency_show() and server_monitor_conn_id_show()
functions use monitor_pages index '0'.

Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>