media: rc: meson-ir: update with SPDX Licence identifier

Remove comment and replace with the appropriate SPDX identifier.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>