ARM: dts: sun8i: V3: add I2S interface to V3 dts

The Allwinner V3 SoC features an I2S interface. The I2S peripheral is
identical to that in the Allwinner H3 SoC.
This commit adds it to the Allwinner V3 dts.

Signed-off-by: Tobias Schramm <t.schramm@manjaro.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210514134405.2097464-8-t.schramm@manjaro.org