hulk inclusion
category: feature
bugzilla: 48159
CVE: NA

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

Register pmem in arm64:
Use memmap(memmap=nn[KMG]!ss[KMG]) reserve memory and
e820(driver/nvdimm/e820.c) function to register persistent
memory in arm64. when the kernel restart or update, the data
in PMEM will not be lost and can be loaded faster. this is a
general features.

driver/nvdimm/e820.c:
The function of this file is scan "iomem_resource" and take
advantage of nvdimm resource discovery mechanism by registering
a resource named "Persistent Memory (legacy)", this function
doesn't depend on architecture.

We will push the feature to linux kernel community and discuss to
modify the file name. because people have a mistaken notion that
the e820.c is depend on x86.

If you want use this features, you need do as follows:
1.Reserve memory: add memmap to reserve memory in grub.cfg
  memmap=nn[KMG]!ss[KMG] exp:memmap=100K!0x1a0000000.
2.Insmod nd_e820.ko: modprobe nd_e820.
3.Check pmem device in /dev exp: /dev/pmem0
Signed-off-by: NZhuLing <zhuling8@huawei.com>
Signed-off-by: NSang Yan <sangyan@huawei.com>
Reviewed-by: NChen Wandun <chenwandun@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>