Add gfx90a target for ROCm CI (#106879)

...in preparation for upgrading CI runners to MI2xx

Pull Request resolved: https://github.com/pytorch/pytorch/pull/106879
Approved by: https://github.com/seemethere
diff --git a/.ci/docker/build.sh b/.ci/docker/build.sh
index 878357f..1f1403c 100755
--- a/.ci/docker/build.sh
+++ b/.ci/docker/build.sh
@@ -375,7 +375,7 @@
        --build-arg "NINJA_VERSION=${NINJA_VERSION:-}" \
        --build-arg "KATEX=${KATEX:-}" \
        --build-arg "ROCM_VERSION=${ROCM_VERSION:-}" \
-       --build-arg "PYTORCH_ROCM_ARCH=${PYTORCH_ROCM_ARCH:-gfx906}" \
+       --build-arg "PYTORCH_ROCM_ARCH=${PYTORCH_ROCM_ARCH:-gfx906;gfx90a}" \
        --build-arg "IMAGE_NAME=${IMAGE_NAME}" \
        --build-arg "UCX_COMMIT=${UCX_COMMIT}" \
        --build-arg "UCC_COMMIT=${UCC_COMMIT}" \