[media] media: rc: gpio-ir-recv: add support for device tree parsing

This patch adds device tree parsing for gpio_ir_recv platform_data and
the mandatory binding documentation. It basically follows what we already
have for e.g. gpio_keys. All required device tree properties are OS
independent but an optional property allows linux specific support for rc
maps.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>