Drivers: hv: vmbus: Don't leak memory when a channel is rescinded

commit 5e030d5ce9d99a899b648413139ff65bab12b038 upstream.

When we close a channel that has been rescinded, we will leak memory since
vmbus_teardown_gpadl() returns an error. Fix this so that we can properly
cleanup the memory allocated to the ring buffers.

Fixes: ccb61f8a99e6 ("Drivers: hv: vmbus: Fix a rescind handling bug")

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>