We currently have some similar code in tlb_fill() and in
arm_cpu_do_unaligned_access() for delivering a data abort or prefetch
abort.  We're also going to want to do the same thing to handle
external aborts.  Factor out the common code into a new function
deliver_fault().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>