drm/i915/mtl: Add fake PCH for Meteor Lake

Correct the implementation trying to detect MTL PCH with
the MTL fake PCH id.

On MTL, both the North Display (NDE) and South Display (SDE) functionality
reside on the same die (the SoC die in this case), unlike many past
platforms where the SDE was on a separate PCH die. The code is (badly)
structured today in a way that assumes the SDE is always on the PCH for
modern platforms, so on platforms where we don't actually need to identify
the PCH to figure out how the SDE behaves (i.e., all DG1/2 GPUs as well as
MTL and LNL),we've been assigning a "fake PCH" as a quickhack that allows
us to avoid restructuring a bunch of the code.we've been assigning a
"fake PCH" as a quick hack that allows us to avoid restructuring a bunch
of the code.

Removed unused macros of LNL amd MTL as well.

v2: Reorder PCH_MTL conditional check (Matt Roper)
Reverting to PCH_MTL for PICA interrupt(Matt Roper)

Signed-off-by: Haridhar Kalvala <haridhar.kalvala@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231219185233.1469675-1-haridhar.kalvala@intel.com

drm/i915/xe2lpd: Add fake PCH

Xe2_LPD doesn't have south display engine on a PCH, it's actually
on the SoC die (while north display engine is on compute die). As
such it makes no sense to go through the PCI devices looking for
an ISA bridge. The approach used by BXT/GLK can't be used here since
leaving it with PCH_NONE would mean taking the wrong code paths.

For the places we currently use a PCH check, it's enough for now to just
check the north display version. Use that to define a fake PCH to be
used across the driver. Eventually these PCH checks may need to be
re-designed as this is already the third platform using/needing a
fake PCH.

v2: Match on display IP version rather than on platform (Matt Roper)
v3: Extend and clarify commit message (Matt Roper / Ville)

Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230919192128.2045154-6-lucas.demarchi@intel.com

drm/i915: add new "soc" sub-directory and move PCH and DRAM code there

Add a new sub-directory for things that aren't specifically about the
GPU and don't really belong in the i915 driver top level, but also don't
belong under any of the existing sub-directories either.

Name it "soc", and move the PCH and DRAM code there.

Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221208142347.602726-1-jani.nikula@intel.com