ubuntu_boot:log_check: drivers/base/memory.c:200 memory_block_action on AWS x1e.xlarge

[Stefan Bader]

Doing boot tests on AWS for xenial:linux(4.4.0-218.251) reported the following dmesg messages:

[ 13.974865] WARNING: CPU: 3 PID: 474 at /build/linux-Bc7FjL/linux-4.4.0/drivers/base/memory.c:200 memory_block_action+0x1a9/0x1d0()
[ 14.750083] WARNING: CPU: 1 PID: 477 at /build/linux-Bc7FjL/linux-4.4.0/drivers/base/memory.c:200 memory_block_action+0x1a9/0x1d0()

This was also seen in an earlier run http://sita/2021.08.16/xenial/linux/4.4.0-214.246/boot-generic-aws-x1e.xlarge-ubuntu_boot-log.html

So this does not seem to be a regression.

The warning is triggered by pages_correctly_reserved() from

```
        /*
         * memmap between sections is not contiguous except with
         * SPARSEMEM_VMEMMAP. We lookup the page once per section
         * and assume memmap is contiguous within each section
         */
        for (i = 0; i < sections_per_block; i++, pfn += PAGES_PER_SECTION) {
                if (WARN_ON_ONCE(!pfn_valid(pfn)))
                        return false;
                page = pfn_to_page(pfn);
```