Drivers: hv: vmbus: Fix a bug in the handling of channel offers

The channel state should be correctly set before registering the device. In the current
code the driver probe would fail for channels that have been rescinded and subsequently
re-offered. Fix the bug.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: stable <stable@vger.kernel.org> # 3.11
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>