pinctrl: rza1: Add support for RZ/A1L

Aspects like the number of ports and the location where peripherals are
brought out differ between the RZ/A1H and RZ/A1L.

Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>