scripts: Add sortextable to sort the kernel's exception table.

Using this build-time sort saves time booting as we don't have to burn
cycles sorting the exception table.

Signed-off-by: David Daney <david.daney@cavium.com>
Link: http://lkml.kernel.org/r/1334872799-14589-2-git-send-email-ddaney.cavm@gmail.com


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>