fix: remove gfx1200 target (not supported by ROCm 6.1 clang 17)

ROCm 6.1's AMD clang 17 doesn't recognize gfx1200 architecture
(introduced in ROCm 6.2+). Caused compilation failure on all .cu files.

ai/ollama/Dockerfile

@@ -51,7 +51,7 @@ RUN mkdir -p build-cpu && cd build-cpu && \
 # Step 2: Build HIP backend with hipcc (legacy mode skips enable_language(HIP))
 RUN mkdir -p build-hip && cd build-hip && \
     CC=hipcc CXX=hipcc cmake .. \
-      -DAMDGPU_TARGETS="gfx906:xnack-;gfx940;gfx1010;gfx1030;gfx1100;gfx1200" \
+      -DAMDGPU_TARGETS="gfx906:xnack-;gfx940;gfx1010;gfx1030;gfx1100" \
       -DCMAKE_BUILD_TYPE=Release && \
     CC=hipcc CXX=hipcc cmake --build . --target ggml-hip -- -l $(nproc) && \
     cmake --install . --component HIP --strip --prefix /build/dist