[PATCH] kdump: NMI handler segment selector, stack pointer fix

CPU does not save ss and esp on stack if execution was already in kernel mode
at the time of NMI occurrence.  This leads to saving of erractic values for ss
and esp.  This patch fixes the issue.

Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>