Add Brother HL-5450DN as supported

[Sebastian Fleer]

I just set up a Brother HL-5450DN with brlaser - it works flawlessly.

Device: uri = usb://Brother/HL-5450DN%20series?serial=E70648K5N269303
        class = direct
        info = Brother HL-5450DN series
        make-and-model = Brother HL-5450DN series
        device-id = MFG:Brother;CMD:PJL,PCL,PCLXL,URF;MDL:HL-5450DN series;CLS:PRINTER;CID:Brother Laser Type2;URF:W8,CP1,IS11-19-4,MT1-3-4-5-8-11,OB10,PQ4,RS300-600-1200,DM1;
        location =