Claude review: drm/bridge: tc358762: Support VTG

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

Patch Review

Adds Video Timing Generator support. When VTG is enabled, the TC358762 generates DPI output timings from its internal registers rather than duplicating DSI input timings. This fixes observed hsync instability.

The implementation:
- Adds VTG register defines (`LCDC_HSR_HBPR`, `LCDC_HDISPR_HFPR`, etc.)
- Converts `drm_display_mode` to `videomode` and programs the timing registers
- Sets `LCDCTRL_VTGEN` and triggers `LCDC_VFUEN` to upload timings
- Adds `use_vtg` flag, hardcoded to `true` in probe

The `use_vtg` field and conditional could be simplified to always-on code since it's hardcoded to `true`, but keeping it as a flag makes the code self-documenting and leaves room for future configurability. This is reasonable.

One observation: `struct videomode vm = { 0 }` — the preferred kernel style is `= { }` or `= {}`, but `= { 0 }` works fine and is common enough.

No issues. **Reviewed-by worthy.**

---
Generated by Claude Code Patch Reviewer