Claude review: gpu: nova-core: convert falcon registers to kernel register macro

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

Patch Review

This is the largest and most complex patch. Key changes:

1. **Enum conversions to `bounded_enum!`**: All falcon enums (`FalconCoreRev`, `FalconCoreRevSubversion`, `FalconSecurityModel`, `FalconModSelAlgo`, `DmaTrfCmdSize`, `PeregrineCoreSelect`, `FalconFbifTarget`, `FalconFbifMemType`) are converted. The `Default` and `repr(u8)` requirements are dropped. `PeregrineCoreSelect` and `FalconFbifMemType` change from `From<bool>` to `From<Bounded<u32, 1>>` which maps to the same semantics.

2. **`FalconEngine` trait simplified**: The `ID` singleton constant is removed since the kernel register macro uses `RegisterBase` generics instead:
```rust
pub(crate) trait FalconEngine:
    Send + Sync + RegisterBase<PFalconBase> + RegisterBase<PFalcon2Base> + Sized
{
}
```

3. **Register access pattern**: Changes from `Reg::read(bar, &E::ID)` / `.write(bar, &E::ID)` to `bar.read(Reg::of::<E>())` / `bar.write(WithBase::of::<E>(), value)`. This is consistent with the kernel macro's API.

4. **`with_falcon_mem` method**: Updated to use `with_const_sec::<1>()` / `with_const_sec::<0>()` instead of `.set_sec(1)` / `.set_sec(0)`. This is the bounded-correct way to set the field.

5. **`NV_PFALCON_FALCON_RM` write**: 
```rust
            regs::NV_PFALCON_FALCON_RM::from(bar.read(regs::NV_PMC_BOOT_0).into_raw()),
```
This uses `From<u32>` to construct the register from a raw value, which is correct since the register is all one 31:0 field.

6. **`FBIF_TRANSCFG` error handling change in bootloader.rs**: 
```rust
-        regs::NV_PFALCON_FBIF_TRANSCFG::try_update(
-            bar,
-            &Gsp::ID,
-            usize::from_safe_cast(self.dmem_desc.ctx_dma),
+        bar.update(
+            regs::NV_PFALCON_FBIF_TRANSCFG::of::<Gsp>()
+                .try_at(usize::from_safe_cast(self.dmem_desc.ctx_dma))
+                .ok_or(EINVAL)?,
```
The error propagation pattern changes: `try_update` returned a `Result` wrapping the whole operation, while now `try_at()` returns `Option` which is converted with `ok_or(EINVAL)?`, and `bar.update()` is infallible. This is functionally equivalent.

7. **Deletion of `regs/macros.rs`**: 739 lines of the old macro infrastructure removed. Clean.

No bugs spotted; the conversion is thorough and correct.

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Generated by Claude Code Patch Reviewer