docs: ABI: stable: remove a duplicated documentation

docs: ABI: stable: remove a duplicated documentation

Perhaps due to a wrong cut-and-paste, this entry:

	What:		/sys/bus/vmbus/devices/<UUID>/channels/<N>/cpu

was added twice by the same patch, one following the other.

Remove the duplication.

Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info")
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/091e8de5543c280ceb47edcb3ab6d0e9f3fa085b.1604042072.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>