arm_mpam: resctrl: Add resctrl_arch_get_config()

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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Implement resctrl_arch_get_config() by testing the configuration for a
CPOR bitmap. For any other configuration type return the default.

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