New kexec-tools wants to pass kdump kernel needed memmap via E820
directly, instead of memmap=exactmap. This makes saved_max_pfn not
be passed down to 2nd kernel. To keep 1st kernel and 2nd kernel using
the same TCE table size, Muli suggest to hard code the size to max (8M).

We can't get rid of saved_max_pfn this time, for backward compatibility
with old first kernel and new second kernel. However new first kernel
and old second kernel can not work unfortunately.

v2->v1:
- retain saved_max_pfn so new 2nd kernel can work with old 1st kernel
  from Vivek
Signed-off-by: NWANG Chao <chaowang@redhat.com>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NMuli Ben-Yehuda <mulix@mulix.org>
Acked-by: NJon Mason <jdmason@kudzu.us>
Link: http://lkml.kernel.org/r/1394463120-26999-1-git-send-email-chaowang@redhat.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>