scheduler: Disable cluster scheduling by default

kunpeng inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5W44S


CVE: NA

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Disable cluster scheduling by default since it's not a universal win.
User can choose to enable it through sysctl or at boot time according to
their scenario.

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Jie Liu <liujie375@h-partners.com>