Drivers: hv: balloon: reset host_specified_ha_region

BugLink: http://bugs.launchpad.net/bugs/1616677

We set host_specified_ha_region = true on certain request but this is a
global state which stays 'true' forever. We need to reset it when we
receive a request where ha_region is not specified. I did not see any
real issues, the bug was found by code inspection.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit d19a55d6)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Acked-by: Kamal Mostafa <kamal@canonical.com>

drivers/hv/hv_balloon.c

@@ -1400,6 +1400,7 @@ static void balloon_onchannelcallback(void *context)
 				 * This is a normal hot-add request specifying
 				 * hot-add memory.
 				 */
+				dm->host_specified_ha_region = false;
 				ha_pg_range = &ha_msg->range;
 				dm->ha_wrk.ha_page_range = *ha_pg_range;
 				dm->ha_wrk.ha_region_range.page_range = 0;