mm: cpufeature: Make update_pbha_perf_only_bit static

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I96IZH



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

Since update_pbha_perf_only_bit is used by current file, make it static.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202403131533.AIOfBKrb-lkp@intel.com/


Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>