arm64: dts: s32g2: add VNP-EVB and VNP-RDB2 support

Add initial device-trees of NXP S32G2's Evaluation Board (S32G-VNP-EVB)
and Reference Design 2 Board (S32G-VNP-RDB2).

Signed-off-by: Chester Lin <clin@suse.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>