etmem: add CONFIG_ETMEM macro definition for etmem feature

euleros inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I7RO5Q
Reference: https://gitee.com/openeuler/kernel/commit/4232d9005401d839ceeb1a02da34749b6dab1376



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add CONFIG_ETMEM macro definition for etmem feature.

Signed-off-by: liubo <liubo254@huawei.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>