drm/i915/tc: Fix TypeC PHY connect/disconnect logic on ADL-P

So far TC-cold was blocked only for the duration of TypeC mode resets.
The DP-alt and legacy modes require TC-cold to be blocked also whenever
the port is in use (AUX transfers, enable modeset), and this was ensured
by the held PHY ownership flag. On ADL-P this doesn't work, since the
PHY ownership flag is in a register backed by the PW#2 power well.
Whenever this power well is disabled the ownership flag is cleared by
the HW under the driver.

The only way to cleanly release and re-acquire the PHY ownership flag
and also allow for power saving (by disabling the display power wells
and reaching DC5/6 states) is to hold the TC-cold blocking power domains
while the PHY is connected and disconnect/reconnect the PHY on-demand
around AUX transfers and modeset enable/disables. Let's do that,
disconnecting a PHY with a 1 sec delay after it becomes idle. For
consistency do this on all platforms and TypeC modes.

v2: Add tc_mode!=disconnected and phy_is_owned asserts to
    __intel_tc_port_lock().

Cc: José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210929132833.2253961-6-imre.deak@intel.com