Drivers: hv: get rid of timeout in vmbus_open()

commit 396e287f upstream.

vmbus_teardown_gpadl() can result in infinite wait when it is called on 5
second timeout in vmbus_open(). The issue is caused by the fact that gpadl
teardown operation won't ever succeed for an opened channel and the timeout
isn't always enough. As a guest, we can always trust the host to respond to
our request (and there is nothing we can do if it doesn't).

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>