arm64: defconfig: drop obsolete ARCH_* configs

Per commit 4a9a1a56 ("arm64: socfpga: merge Agilex and N5X into
ARCH_INTEL_SOCFPGA") and commit 89d4f98a ("ARM: remove zte zx
platform"), they can be dropped from defconfig now.

Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>