x86/resctrl: Make prefetch_disable_bits belong to the arch code

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8T2RT

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/log/?h=mpam/snapshot/v6.7-rc2



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prefetch_disable_bits is set by rdtgroup_locksetup_enter() from an
arch code value, then read by the arch code.

Instead of exporting this value, make
resctrl_arch_get_prefetch_disable_bits() set it so that the other
arch-code helpers can use the cached-value.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Zeng Heng <zengheng4@huawei.com>