package/dvb-apps: fix licensing terms when utils are enabled

When the dvb-apps utilities are selected, the license is clearly a
mix of GPLv2, GPLv2+ and LGPLv2.1+; this, in addition to the initial
unknown license for the transponders data.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>