There are multiple variants of DW HDMI PHYs in Allwinner SoCs. While
some things like clock and reset setup are the same, PHY configuration
differs a lot.

Split out code which is PHY specific to separate functions and create
a structure which holds pointers to those functions.
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180301213442.16677-11-jernej.skrabec@siol.net