[HIP/ROCm] BF16 inference fails: layer_norm kernel not registered for bfloat16 + conv2d fuse passes crash

## Problem When running PaddleOCR-VL-1.5 in BF16 mode on AMD ROCm (gfx1100 / ROCm 7.2.0), two errors occur: ### Error 1: conv2d fuse passes crash on ROCm ``` Cannot find the kernel for [FusedConv2dAddAct] on GPU with float32 ``` The `conv2d_add_act_fuse_pass` and `conv2d_add_fuse_pass` generate `FusedConv2dAddActOp` nodes, but this op is only compiled under `PADDLE_WITH_CUDA` (not HIP). PaddleX worked around this by calling `config.delete_pass()` in every inference session. ### Error 2: layer_norm kernel not registered for bfloat16 on HIP ``` NotFound: Cannot find the kernel for [layer_norm] on GPU with bfloat16. ``` The HIP `PD_REGISTER_KERNEL` block in `paddle/phi/kernels/gpu/layer_norm_kernel.cu` only registers `float` and `float16`. The `LayerNormKernel` implementation uses templated CUDA-compatible intrinsics that compile and run correctly on ROCm, but `bfloat16` was never registered. ## Reproduction Hardware: AMD Radeon RX 7900 GRE (gfx1100), ROCm 7.2.0, Python 3.12 ```python import paddle import paddle.nn as nn # Triggers Error 2 x = paddle.randn([4, 64]).cast(paddle.bfloat16).cuda() ln = nn.LayerNorm(64).to(dtype=paddle.bfloat16) out = ln(x) # NotFound: Cannot find kernel for layer_norm on GPU with bfloat16 ``` For Error 1, any BF16 inference session using PaddleX static inference with `dtype='bfloat16'` and a model containing Conv2d will trigger it. ## Impact PaddleOCR-VL-1.5 (SigLIP visual encoder uses BF16 conv + layer_norm) cannot run in BF16 on AMD ROCm without workarounds. ## Fix PR submitted: see linked PR. - `conv2d_add_act_fuse_pass.cc` / `conv2d_add_fuse_pass.cc`: add `#ifdef PADDLE_WITH_HIP` guard in `InitializePatterns()` returning empty pattern set - `layer_norm_kernel.cu`: add `phi::bfloat16` to HIP `PD_REGISTER_KERNEL` ## Validation After fix, on gfx1100 / ROCm 7.2.0: - LayerNorm BF16 SNR vs FP32: **44 dB** (excellent) - PaddleOCR-VL-1.5 full BF16 pipeline: load 14.6s, inference 202.8s, **EXIT:0** - OCR output correct