hv_vmbus: Correct the stale comments regarding cpu affinity

The comments doesn't match what the current code does, also have a
typo. This patch corrects them.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>