kdump: fix gdb macros work work with newer and 64-bit kernels

Lots of little changes needed to be made to clean these up, remove the
four byte pointer assumption and traverse the pid queue properly.  Also
consolidate the traceback code into a single function instead of having
three copies of it.

Link: http://lkml.kernel.org/r/1462926655-9390-1-git-send-email-minyard@acm.org


Signed-off-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Haren Myneni <hbabu@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>