[ROCm] Guard group quant RMS norm fusion patterns (#30239)

vllm/compilation/fusion.py

@@ -490,6 +490,8 @@ class RMSNormQuantFusionPass(VllmPatternMatcherPass):
         # as the latter is a subset of the former in torch ops
         for epsilon in [1e-5, 1e-6]:
             # Fuse fused_add_rms_norm + fp8 group quant
+            # Only register group quant patterns on CUDA where the C++ op exists
+            if current_platform.is_cuda():
                 FusedAddRMSNormGroupQuantPattern(
                     epsilon, FP8_DTYPE, group_shape=GroupShape(1, 128)
                 ).register(self.patterns)