[ARM] Add support for pause_on_oops and display preempt/smp options

Add calls to oops_enter() and oops_exit() to __die(), so that
things like lockdep know when an oops occurs.

Add suffixes to the oops report to indicate whether the running
kernel has been built with preempt or smp support.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>