mpam: Add support for group rmid modify

ascend inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4L735


CVE: NA

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The mpam driver controls the allocation of rmid, however there
are some ocassions that the partid and pmg of a group might come
from elsewhere. This add support for group rmid modify. The
sysfs rmid file is set to write accessible, and this add a write
interface to accept rmid from user. When the rmid from user is
different and valid, update the group with new rmid. When error
occurs, rollback to old rmid.

Signed-off-by: Xingang Wang <wangxingang5@huawei.com>
Reviewed-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
Reviewed-by: Weilong Chen <chenweilong@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>