[PATCH v5] Support to filter dump for kernels that use CONFIG_SPARSEMEM_VMEMMAP.

Makedumpfile tool fails to filter dump for kernels that are build with
CONFIG_SPARSEMEM_VMEMMAP set, as it fails to do address translations
for vmemmap regions that are mapped out of zone normal. This patch
provides support in makedumpfile to do vmemmap to physical address
translations when they are mapped outside zone normal. Some kernel
symbols are needed in vmcoreinfo for this changes to be effective.
The kernel patch that adds the necessary symbols to vmcoreinfo has
been posted to linuxppc devel mailing list. This patch is influenced
by vmemmap to physical address translation support code in crash tool.
This patch has been tested successfully at all dump filtering levels
on kernels with CONFIG_SPARSEMEM_VMEMMAP set/unset. Also, tested dump
filtering on already filtered vmcores (re-filtering).

Changes from v4 to v5:
Trimmed patch description to be compact and readable.

Changes from v3 to v4:
Rebased to devel branch.

Signed-off-by: Onkar N Mahajan <onmahaja@in.ibm.com>
Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>