In specification
A device is defiend as below,

Device: A device is a collection of compute units. A command-queue is used to queue
commands to a device. Examples of commands include executing kernels, or reading and writing memory objects. OpenCL devices typically correspond to a GPU, a multi-core CPU, and other processors such as DSPs and the Cell/B.E. processor.

Does this mean a platform cannot have more than one device of type CPU which is being host CPU/multicore CPU?
Or would it be implementation defined?