dt-bindings: sram: sunxi-sram: Add H616 compatible string

The H616 adds a second EMAC clock register. We don't know about the
exact SRAM properties yet, so this gets omitted for now.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210127172500.13356-8-andre.przywara@arm.com