drm/sun4i: sun8i-hdmi-phy: Support multiple custom PHY ops

The D1 SoC comes with a new custom HDMI PHY, which does not share any
registers with the existing custom PHY. So it needs a new set of ops.
Instead of providing a flag in the variant structure, provide the ops
themselves.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220615045543.62813-5-samuel@sholland.org