Revert "arm64/mpam: Fix mpam corrupt when cpu online"

hulk inclusion
category: bugfix
bugzilla: 189067, https://gitee.com/openeuler/kernel/issues/I7PN0A


CVE: NA

-------------------------------------------------

BUG 'sleeping function called from invalid context' reported when
setup MPAM driver, it was blamed to 0f4acaeb ("arm64/mpam:
Fix mpam corrupt when cpu online"), which reported a 'Bad PC' BUG,
but missing the right conclusion, finally disabling irqs before calling
cpuhp_setup_state() may only affect the probability of reproduction.

The reason why triggerring 'Bad PC' BUG report is because mpam_enable()
is __init type function, and may schedule out after calling
__cpuhp_setup_state()->__might_sleep(), so the space of mpam_enable()
might be freed after scheduling back.

As we have changed mpam_enable() to non-init type function, we can
revert commit 0f4acaeb directly, to solve these both two problems.

Fixes: 0f4acaeb ("arm64/mpam: Fix mpam corrupt when cpu online")
Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>