drm/i915/psr: Bring back HSW/BDW PSR AUX CH registers/setup

Reintroduce the special PSR AUX CH setup for hsw/bdw. Not all
of it was even removed (BDW AUX data registers were left behind).
Update the code to use REG_BIT() & co. while at it.

v2: Define the SRD_AUX_CTL bits in terms of DP_AUX_CTL bits (Jouni)
Add a comment explaining the hand rolled DPCD write (Jouni)

Cc: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230609141404.12729-6-ville.syrjala@linux.intel.com
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>

drm/i915/irq: relocate gmbus and dp aux irq handlers

Move gmbus and dp aux irq handlers to their respective files. It should
be up to them what to do with the irq, not the generic irq code.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e825385fc03cb3d53c1f0b66712eea42dad69d59.1683219363.git.jani.nikula@intel.com

drm/i915: Restructure intel_bios_port_aux_ch()

Restructure intel_bios_port_aux_ch() to resemble the ddc_pin
counterpart, where the intel_bios.c stuff only deals with the
child device definition, and the platform default will come from
elsewhere.

This requires the introduction of AUX_CH_NONE as the value 0
is already taken to mean AUX_CH_A.

v2: Sort includes alphabetically (Ankit)
vCould we ask them to do a BIOS fix for all of them so that
we wouldn't keep getting these bug reports for each model
separately?

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230216231312.32664-1-ville.syrjala@linux.intel.com
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>

drm/i915/dp: make intel_dp_pack_aux() static again

The last user of intel_dp_pack_aux() outside intel_dp_aux.c got removed
in commit ad26451a7902 ("drm/i915/display: Drop PSR support from HSW and
BDW"). Make the function static again.

Rename the pack/unpack functions to follow the usual naming conventions
while at it.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220112105703.1151391-1-jani.nikula@intel.com

drm/i915/dp: split out aux functionality to intel_dp_aux.c

Split out the DP aux functionality to a new intel_dp_aux.[ch]. This is a
surprisingly clean cut.

v2:
- Remove intel_dp_pack_aux declaration from intel_dp.h (Anshuman)
- Fixed some whitespace/comment checkpatch warnings

Cc: Anshuman Gupta <anshuman.gupta@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210120101834.19813-4-jani.nikula@intel.com