ima: fix CONFIG_IMA_DIGEST_DB_MEGABYTES in openeuler_defconfig

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I409K9


CVE: NA

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Commit 7c9d18bc ("ima: Add max size for IMA digest database") adds
a new Kconfig for IMA Digest Lists: CONFIG_IMA_DIGEST_DB_MEGABYTES.
However, that commit has typos in openeuler_defconfig. This patch is
to fix that typo.

Fixes: 7c9d18bc ("ima: Add max size for IMA digest database")
Signed-off-by: Zhang Tianxing <zhangtianxing3@huawei.com>
Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>