drm/sun4i: sun8i-hdmi-phy: Separate A83T and H3 PHY ops

Since the driver already needs to support multiple sets of ops, we can
drop the mid-layer used by the A83T and H3 PHYs. They share only a small
amount of code; factor this out as sun8i_hdmi_phy_set_polarity.

For clarity, this commit keeps the existing function order.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220615045543.62813-6-samuel@sholland.org