Claude review: dma-buf: dma-heap: Keep track of the heap device struct

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

Patch Review

**From John Stultz, carried by Albert Esteve.**

This patch stores the `device *` returned by `device_create()` in `heap->heap_dev` instead of a local variable, and adds a `dma_heap_get_dev()` accessor.

**Issues:**

1. **Spurious `get_device()` and extra blank line.** The patch adds:
```c
+	/* Make sure it doesn't disappear on us */
+	heap->heap_dev = get_device(heap->heap_dev);
+
+
	/* Add heap to the list */
```
There's a double blank line here (minor style). More importantly, this `get_device()` takes an extra reference on a device that was just created by `device_create()` -- the heap already holds a reference from creation, and there is no corresponding `put_device()` in any error or teardown path in this patch. This leaks a refcount. Patch 2 restructures things and removes this `get_device()`, but in the meantime patch 1 is broken in isolation. Ideally each patch should be correct standalone (bisectability).

2. **The `heap_dev` pointer is not cleaned up on the `err3` path** (duplicate name). If `device_create()` succeeds but the name check fails, `heap_dev` is stored in the struct but `device_destroy()` cleans up by devt. The field is then freed with `kfree(heap)`. This is fine functionally, but the extra `get_device()` above means the device won't actually be freed. Again, this is resolved in patch 2, but patch 1 in isolation has a refcount leak.

---
Generated by Claude Code Patch Reviewer