Do not call cpu_restore_state when no exception will be
delivered.  This can lead to inconsistent cpu state.

Tested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Reported-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>