ARM: multi_v7_defconfig: Enable support for RZ/A2

Enable support for the RZ/A2 SoC, including pin control, now the DTS for
the Renesas RZ/A2M evaluation board is included.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>