[PATCH v3 5/7] makedumpfile: Correct the calculation of kvaddr in set_kcore_vmcoreinfo

In set_kcore_vmcoreinfo, we calculate the virtual address of vmcoreinfo
by OR operation as below:

	kvaddr = (ulong)vmcoreinfo_addr | PAGE_OFFSET;

When mm sections kaslr is not enabled, this is correct since the
starting address of direct mapping section is 0xffff880000000000 which
is 1T aligned.  Usually system with memory below 1T won't cause problem.

However with mm section kaslr enabled, the starting address of direct
mapping is 1G aligned. The above code makes kvaddr unsure.

So change it to adding operation:
	kvaddr = (ulong)vmcoreinfo_addr + PAGE_OFFSET;

Signed-off-by: Baoquan He <bhe@redhat.com>