arm64/mpam: Fix buffer overflow in mpam_handle_error_irq()

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8EF0Z



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Fix buffer overflow in mpam_handle_error_irq():
mpam_handle_error_irq() error: buffer overflow 'mpam_msc_err_str' 8 <= 8

Fixes: 44513976 ("arm64/mpam: Enabling registering and logging error interrupts")
Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>