drm/komeda: Add new component komeda_splitter

Similar to Layer Split, but Splitter is used for writeback, which splits
the compiz result to two half parts and then feed them to two scalers.

v2: Rebase

Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>

drm/komeda: Add component komeda_merger

Introduce a new component komeda_merger, because D71 HW supports to split
a whole image to two half parts and does the scaling independently. Merger
merges two separate results to one, and output it to compositor or wb_layer
For this patch:
- Add the definition of komeda_merger/merger_state
- Report and initialize komeda_merger according to the D71 HW.

v2: Rebase

Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>

drm/komeda: Attach scaler to drm as private object

According to the komeda pipeline configuration, attach scaler to drm as
private object.

v2: Rebase

Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>

drm/komeda: Add writeback support

Komeda driver uses a individual component to describe the HW's writeback
caps, but drivers doesn't define a new structure and still uses the
existing "struct komeda_layer" to describe this new component.
The detailed changes as follow:

1. Initialize wb_layer according to HW and report it to CORE.
2. CORE exposes wb_layer as a resource to KMS by private_obj.
3. Report writeback supporting by add a wb_connector to KMS, and then
wb_connector will take act as a component resources user,
so the func komeda_wb_encoder_atomic_check claims komeda resources
(scaler and wb_layer) accroding to its state configuration to the
wb_connector. and the wb_state configuration will be validated on the
specific component resources to see if the caps of component can
meet the requirement of wb_connector. if not check failed.
4. Update irq_handler to notify the completion of writeback.

NOTE:
This change doesn't add scaling writeback support, that support will
be added in the future after the scaler support.

v2: Rebase
v3: Rebase and constify the d71_wb_layer_funcs
v4: Addressed Ayan's comments

Depends on:
- https://patchwork.freedesktop.org/series/59915/

Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Acked-by: Ayan Kumar Halder <ayan.halder@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>

drm/komeda: Initialize komeda component as drm private object

Initialize koemda_layer, komeda_compiz, komeda_improc and
komeda_timing_ctrlr as drm private object, then track komeda private
component state by drm_atomic_state.

v2:
- Update code after Applied commit:
b962a12050a3 ("drm/atomic: integrate modeset lock with private objects")

Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>

drm/komeda: Attach komeda_dev to DRM-KMS

Add komeda_kms abstracton to attach komeda_dev to DRM-KMS
CRTC: according to the komeda_pipeline
PLANE: according to komeda_layer (layer input pipeline)
PRIVATE_OBJS: komeda_pipeline/component all will be treat as private_objs

komeda_kms is for connecting DRM-KMS and komeda_dev, like reporting the
kms object properties according to the komeda_dev, and pass/convert KMS's
requirement to komeda_dev.

Changes in v4:
- Set drm_atomic_helper_check as mode_config->atomic_check.

Changes in v3:
- Fixed style problem found by checkpatch.pl --strict.

Changes in v2:
- Unified abbreviation of "pipeline" to "pipe".

Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>