SIGBUS crash in RenderHal_Initialize using VA-API with Arc B580 (Battlemage G21)

**Describe the bug**

Running `vainfo` on Intel Arc B580 (Battlemage G21) with the `iHD` driver results in a **SIGBUS (Bus error)** crash during heap initialization in `RenderHal_Initialize`.

The issue appears in `memset()` during state heap interface setup.

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**To Reproduce**

Steps to reproduce the behavior:

1. Use Ubuntu 25.04 with latest kernel and Mesa stack.
2. Install `intel-media-driver` with `iHD` support.
3. Ensure `LIBVA_DRIVER_NAME=iHD` and run:

```bash
vainfo
```
4. Observe a SIGBUS crash.

---

**Expected behavior**

`vainfo` should detect and list supported VA-API profiles using the iHD driver.

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**Stack trace (from GDB)**

```
Program received signal SIGBUS, Bus error.
__memset_avx2_unaligned_erms () at ../sysdeps/x86_64/multiarch/memset-vec-unaligned-erms.S:210

#0 __memset_avx2_unaligned_erms ()
#1 0x00007ffff5e45973 in XMHW_STATE_HEAP_INTERFACE::InitializeInterface (
this=0x555555604230, StateHeapSettings=...)
at /media-driver/media_softlet/agnostic/common/hw/mhw_state_heap.cpp:1083
#2 0x00007ffff5e45d27 in Mhw_StateHeapInterface_Create (
ppStateHeapInterface=, StateHeapSettings=...)
at /media-driver/media_softlet/agnostic/common/hw/mhw_state_heap.cpp:680
#3 0x00007ffff5d8676b in mhw::render::Impl::AllocateHeaps (this=, stateHeapSettings=...)
at /media-driver/media_softlet/agnostic/common/hw/mhw_render_impl.h:167
#4 0x00007ffff5d39dcf in XRenderHal_Platform_Interface_Next::AllocateHeaps (
this=, pRenderHal=, MhwStateHeapSettings=...)
at /media-driver/media_softlet/agnostic/common/renderhal/renderhal_platform_interface_next.cpp:807
#5 0x00007ffff5d36b04 in RenderHal_AllocateStateHeaps (
pRenderHal=0x5555556017b0, pSettings=0x555555601858)
at /media-driver/media_softlet/agnostic/common/renderhal/renderhal.cpp:1499
#6 0x00007ffff5d35005 in RenderHal_Initialize (pRenderHal=0x5555556017b0, ...
```

---

**Environment**

* **GPU**: Intel Arc B580 (Battlemage G21)
* **Kernel**: 6.15.0-rc4+
* **OS**: Ubuntu 25.04 (plucky)
* **Media driver version**: latest build from source (May 4, 2025)
* **libva version**: 2.22.0
* **vainfo**: crashes with `SIGBUS`
* **Mesa version**: 25.0.3

---

**Additional context**

* The crash happens regardless of Wayland/X11.
* Mesa VA driver (`mesa_drv_video.so`) does not support this hardware.
* User is in `render` group, permissions are correct.

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**Suggested label**: `bug`, `Battlemage`, `Arc`, `SIGBUS`, `heap allocation`, `VAAPI`

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