The arm64 defconfig builds failed on the Linux next-20251002 tag build due to following build warnings / errors with gcc-8 toolchain.

* arm64, build - gcc-8-defconfig

First seen on next-20251002 Good: next-20250929 Bad: next-20251002..next-20251003

Regression Analysis: - New regression? yes - Reproducibility? yes

Build regression: next-20250102: arm64: gcc-8-defconfig: Assembler messages: Error: unknown architectural extension `simd;'

Reported-by: Linux Kernel Functional Testing lkft@linaro.org

### Build error log /tmp/cclfMnj9.s: Assembler messages: /tmp/cclfMnj9.s:656: Error: unknown architectural extension `simd;' make[8]: *** [scripts/Makefile.build:287: drivers/net/ethernet/mellanox/mlx5/core/wc.o] Error 1

Suspecting commit, $ git blame -L 269 drivers/net/ethernet/mellanox/mlx5/core/wc.c fd8c8216648cd8 (Patrisious Haddad 2025-09-29 00:08:08 +0300 269) (".arch_extension simd;\n\t" fd8c8216648cd net/mlx5: Improve write-combining test reliability for ARM64 Grace CPUs

## Source * Kernel version: 6.17.0 * Git tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git * Git commit: 47a8d4b89844f5974f634b4189a39d5ccbacd81c * Architectures: arm64 * Toolchains: gcc-8 * Kconfigs: defconfig

## Build * Build log: https://storage.tuxsuite.com/public/linaro/lkft/builds/33YUHcFKTLSBTOxNIJqF9... * Build details: https://regressions.linaro.org/lkft/linux-next-master/next-20251003/build/gc... * Build plan: https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/builds/33YUHcFKTL... * Build link: https://storage.tuxsuite.com/public/linaro/lkft/builds/33YUHcFKTLSBTOxNIJqF9... * Kernel config: https://storage.tuxsuite.com/public/linaro/lkft/builds/33YUHcFKTLSBTOxNIJqF9...

-- Linaro LKFT