Can I combine both Roth TSP (military) and Roth IRA (civilian company) contributions toward the "retirement savings contributions credit"? Total contribution = $7.5K

I use both a Roth IRA and the Roth TSP to save for retirement. Can I combine the 2017 contributions for both accounts toward the "retirement savings contributions credit"? The Roth IRA total was $4.5K and the Roth TSP total was $2056. So combined total is more than the $5.5K allowed by the US gov.