package/gpu-viv-bin-mx6q: only available for i.MX6Q

Signed-off-by: Gary Bisson <bisson.gary@gmail.com>
[yann.morin.1998@free.fr: split from the previous patch]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Hadrien Boutteville <hadrien.boutteville@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>