Claude review: drm/msm/dsi: Support dual panel use case with single CRTC

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

**Concept**: When `is_dual_panel` is set, halves `dsc->pic_width` and `pic_width` in check_dsc so the DSI host configures DSC for a single panel's width.

**Issues:**

1. **Correct fix for `dsc->pic_width`**: In `dsi_timing_setup()`, the existing code (line 1033 upstream) sets `dsc->pic_width = mode->hdisplay`, which is indeed wrong for bonded DSI since `mode->hdisplay` is the full doubled width. The patch changes this to use `hdisplay` (the local variable), which is correct for bonded DSI (`hdisplay` was already halved on line 1019). However, the patch uses `msm_host->is_dual_panel` to decide, while the existing `is_bonded_dsi` parameter already covers this case. This creates two overlapping concepts:
   - `is_bonded_dsi`: the existing bonded DSI path (already halves timings)
   - `is_dual_panel`: the new dual-panel path
   
   The patch only sets `dsc->pic_width = hdisplay` when `is_dual_panel` is true, but `hdisplay` has already been halved for `is_bonded_dsi` as well. So for the existing bonded-DSI-with-single-panel case, `dsc->pic_width` is still set to `mode->hdisplay` (the full width), which appears to be a pre-existing bug that this patch doesn't fix. The relationship between these two flags needs clarification.

2. **`msm_dsi_host_check_dsc` fix is incomplete**: The patch adds:
   ```c
   if (msm_host->is_dual_panel)
       pic_width = mode->hdisplay / 2;
   ```
   But `pic_width` was already initialized to `mode->hdisplay` on the previous line. The fix works but note that `is_bonded_dsi` (the existing bonded DSI flag, not dual_panel) also requires halving for the pre-existing single-panel bonded case. This function currently has no concept of `is_bonded_dsi` at all, which may be an existing limitation.

3. **Commit message typo**: "togehter" → "together" in line "While the DSI panel driver should manage two panels togehter."

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