arm64: defconfig: Remove the redundant SCHED_MC/SCHED_SMT

arm64: defconfig: Remove the redundant SCHED_MC/SCHED_SMT

The patch "7bd291abe2d sched: Unify the SCHED_{SMT,CLUSTER,MC} Kconfig"
has enabled the SCHED_MC/SCHED_SMT by default for arm64.

So remove the redundant code in defconfig.

Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
Link: https://lore.kernel.org/r/20251021075704.527626-1-shijie@os.amperecomputing.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>