mtd: Add several functions to the fail_function list

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I60L5U


CVE: NA

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add mtd_read() mtd_write() mtd_erase() to fail_function list for
testing purpose

Signed-off-by: ZhaoLong Wang <wangzhaolong1@huawei.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>