[media] rtl28xxu: Add USB ID for Leadtek WinFast DTV Dongle mini

USB ID 0413:6a03 is Leadtek WinFast DTV Dongle mini.
Decoder Realtek RTL2832U and tuner Infineon TUA9001.

Signed-off-by: Miroslav Šustek <sustmidown@centrum.cz>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>