fpga: dfl: afu: add port ops support

This patch registers the port ops into the global list in the DFL
framework, and it allows other modules to use the port ops. And
This patch includes the implementation of the get_id and enable_set
ops too.

Signed-off-by: Wu Hao <hao.wu@intel.com>
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>