ARM: mxs: Add OF props for MX23 LRADC

Add interrupt mapping and compatible string for MX23 LRADC.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>