The firmware included commits for other hardware to support future op25. These commits/changes do not apply to the Slate 7 and there is no op25 release for this device coming at this time (Until Qualcomm release an SDK that support newer OpenWRT). I believe the line you mention here applies to the Flint 2 and Beryl AX only but would need to find the other thread where this was discussed.
Edit: See here