KDUMP: skip indirection page, as crashkernel has already copied to destination

[ralf@linux-mips.org: cosmetic changes.]
Signed-off-by: Prem Mallappa <pmallappa@caviumnetworks.com>
Cc: linux-mips <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/5786/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>