Claude review: drm/tegra: gr2d/gr3d: Move pm_runtime_enable to gr*d_probe

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

Patch Review

**Issue: Wrong ordering of pm_runtime calls (moderate)**

In both gr2d and gr3d, the patch adds:

```c
pm_runtime_enable(dev);
pm_runtime_use_autosuspend(dev);
pm_runtime_set_autosuspend_delay(dev, 500);
```

The standard kernel pattern is the reverse — configure autosuspend *before* enabling runtime PM:

```c
pm_runtime_set_autosuspend_delay(dev, 500);
pm_runtime_use_autosuspend(dev);
pm_runtime_enable(dev);
```

Once `pm_runtime_enable()` is called, the runtime PM subsystem is live and can immediately attempt to suspend the device. If autosuspend isn't configured yet, there's a window where a `pm_runtime_put()` could trigger an immediate suspend rather than the intended 500ms delayed autosuspend. The delay should be set first, then autosuspend enabled, then finally runtime PM enabled.

This ordering issue existed in the original `runtime_resume` code too, but there it was less consequential since the device was already actively resuming. In `probe()`, with PM freshly enabled, it matters more.

**Observation: Placement relative to host1x_client_register (minor)**

The `pm_runtime_enable()` is placed after `host1x_client_register()`. If the host1x framework synchronously invokes `gr*d_init()` during registration, and that callback (or anything it triggers) does `pm_runtime_get_sync()`, the resume callback won't fire because runtime PM isn't enabled yet. In practice this is likely safe because `host1x_client_register` just adds the client to a list, but it's worth considering whether enabling PM before registration would be more robust. That would require adding `pm_runtime_disable()` to the error path for `host1x_client_register()` failure though.

**Observation: Missing Fixes tag**

If this addresses a real bug (runtime PM never properly enabled on first boot without a sleep/resume cycle), a `Fixes:` tag referencing the commit that originally placed `pm_runtime_enable` inside `runtime_resume` would help stable backport triage.

**Style nit: gr3d uses `&pdev->dev` vs gr2d uses `dev`**

In `gr2d_probe`, there's a local `struct device *dev = &pdev->dev;`, so the patch correctly uses `dev`. In `gr3d_probe`, there's no such local variable, so `&pdev->dev` is used. This is consistent with the existing code in each file — no issue, just noting the difference.

**Summary**: The change is correct in principle and fixes a real bug. Please reorder the three calls so `pm_runtime_enable()` comes last (after configuring autosuspend), and consider adding a `Fixes:` tag.

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