Build error: conflicting types for 'class_mutex_t' on kernel 7.0.0-14-generic

## Build error: conflicting types for `class_mutex_t` on kernel 7.0.0-14

### Description

Running `sudo make install` fails to compile the ixgbe driver against Linux kernel 7.0.0-14-generic (default kernel on Ubuntu 26.04). The compiler reports a conflicting type error in the kernel's `cleanup.h` header.

### Environment

- **Kernel version:** 7.0.0-14-generic
- **Driver:** ixgbe (latest from this repo)
- **Command:** `sudo make install`

### Error output

```
/usr/src/linux-headers-7.0.0-14-generic/include/linux/cleanup.h:280:15: error: conflicting types for 'class_mutex_t'; have 'struct mutex *'
280 | typedef _type class_##_name##_t;
```

### Root cause (suspected)

It appears the ixgbe driver or one of its headers defines a symbol that conflicts with the `class_mutex_t` typedef introduced (or changed) in kernel 7.0.0-14 via `include/linux/cleanup.h`. This is likely a macro expansion clash — the `CLASS()` macro in `cleanup.h` generates typedefs like `class__t`, and if the driver defines a `mutex` class guard internally, the resulting typedef conflicts with an already-declared `struct mutex *` type.

### Steps to reproduce

1. Install kernel `7.0.0-14-generic` and its headers
2. Clone this repository
3. Run `sudo make install`
4. Observe the build error above

### Additional notes

Please let me know if you need any additional debug output, kernel config, or compiler version details.