adb: host: Fix windows build after 5c0999c2

* Windows fd_set struct uses SOCKET type,
  therefore we need to cast device_fd to
  cutils_socket_t so that it's int on
  Linux and SOCKET on Windows, otherwise
  we might get comparison of integers of
  different signs error.

Change-Id: I13357dff5563fbbafb59cfc34b2e8ccdf7b86a79