ARM: dts: sunxi: Fix the HDMI PHY name

Even though the binding mentions that the PHY name must be "phy", it turns
out that all our DTs had "hdmi-phy" instead.

The code doesn't care about the phy-names property, so we can just change
our DTs to match the binding, without any side effect.

Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>