Hello,
If it is not in the spec sheet it is not supported:
http://www.cisco.com/c/dam/en/us/products/collateral/servers-unified-computing/ucs-c-series-rack-servers/c220m4-sff-spec-sheet.pdf
With that in mind, you could try to use it in your server and it could potentially work. However, if you ever had an issue with the server and had to open a TAC case, etc the card is the first item that would be pointed at as a problem.
Thanks,
Justin