[media] rc: meson-ir: remove irq from struct meson_ir

The irq number is used in the probe function only, therefore just use
a local variable.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>