Broadband Deployment Streamlining Act This bill directs the Department of the Interior, for public lands, and the Department of Agriculture, for National Forest System lands, to issue regulations to: (1) streamline the process for the consideration of applications to locate or modify communications facilities on such lands; and (2) require that such applications be considered and granted on a neutral and non-discriminatory basis. The bill amends the Middle Class Tax Relief and Job Creation Act of 2012 to require executive agencies to grant or deny within 270 days applications for an easement or right-of-way on federal property to install, construct, and maintain wireless service antenna structures and equipment and backhaul transmission equipment. The Government Accountability Office shall report on: how the Federal Communications Commission (FCC) ensures that the broadband data collected for the National Broadband Map is accurate, complete, and reliable; the extent to which federal agencies or other entities authorized to distribute federal grants or loans for broadband projects rely on such data; FCC actions to address the limitations on using such data for policy or funding decisions; the extent to which interested parties have challenged the accuracy of information on the map; and whether the FCC should collect such data from additional or alternative commercial sources.