[media] rc: img-ir: Expand copyright headers with GPL notices

Add the basic GPLv2+ license notice to the copyright headers at the top
of all the source files in the img-ir driver.

Reported-by: David Härdeman <david@hardeman.nu>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>