config: enable bcache for x86 by default

driver inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6N4EP


CVE: NA

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openEuler supports bcache by default on x86 platforms,
Solve the kabi change caused by opening bcache.

Signed-off-by: Chao Zhu <tom_toworld@163.com>