ARM: dts: mstar: Add a dts for M5Stack UnitV2

M5Stack are releasing a new widget based on the
SigmaStar SSD202D. We have some support for the
SSD202D so lets add a dts for it.

Signed-off-by: Daniel Palmer <daniel@0x0f.com>
Link: https://m5stack-store.myshopify.com/products/unitv2-ai-camera-gc2145
Link: https://lore.kernel.org/r/20210417011015.2105280-4-daniel@0x0f.com

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Signed-off-by: Arnd Bergmann <arnd@arndb.de>