[media] vivid-tpg: add support for SMPTE 2084 transfer function

Support the new SMPTE 2084 transfer function in the test pattern generator.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>