The HDMI PHY in the BCM2711 HDMI controller is significantly more
complicated to setup than in the older BCM283x SoCs.

Let's add hooks to enable and disable the PHY.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/7216826284dbc60a58bdacd662805d20699e5c80.1599120059.git-series.maxime@cerno.tech