To differentiate Ethernet clocks from regular clocks, the interface parameter 'TYPE' is defined in the schema. This parameter provides additional filtering while searching an appropriate IP for a board interface. The value of the TYPE parameter should be the same in the board interface and the IP interface.
For example, the sgmii_mgt_clk interface in the KC705 board has the TYPE parameter with the value defined as ETH_MGT_CLK. Similarly the IP component.xml file has the interface parameter TYPE =ETH_MGT_CLK.
See <vivado_install_dir>/data/ip/xilinx/gig_ethernet_pcs_pma_v15_0/component.xml as an example.