arm64/mpam: Not allowed setting 0 to cache portion bit mask

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I9H4YE



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Not allowed cache portion to be set to 0, and this kind of operation is
not supported by hardware.

Fixes: 58e843d9 ("arm64/mpam: resctrl: Support priority and hardlimit(Memory bandwidth) configuration")
Signed-off-by: Zeng Heng <zengheng4@huawei.com>