doc: soc: hisilicon: Add Kunpeng HCCS driver documentation

mainline inclusion
from mainline-v6.6-rc1
commit b51022b4
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I81QY0
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v6.6-rc1&id=b51022b416f5be113cd5345a2cab287d78e6b74c



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

Document the sysfs attributes description provided by HCCS driver on
Kunpeng SoC.

Signed-off-by: Huisong Li <lihuisong@huawei.com>
Signed-off-by: Wei Xu <xuwei5@hisilicon.com>