arm64/mpam: Squash default priority from mpam device to class

hulk inclusion
category: feature
feature: ARM MPAM support
bugzilla: 48265
CVE: NA

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

Store default priority in mpam class structure from reading devices'
intpri_wd and dspri_wd.

intpri_wd and dspri_wd represent the number of implemented bits in the
internal/downstream priority field in MPAMCFG_PRI, when INTPRI_0_IS_LOW
/DSPRI_0_IS_LOW is not set, we need to rotate input priority(higher value
higher priority) from user space to target priority (higher value lower
priority) and this is restricted by implemented bits.

Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Reviewed-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: Cheng Jian <cj.chengjian@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>