configs: socfpga: soc64: Avoid SPL enter infinite loop during exception

configs: socfpga: soc64: Avoid SPL enter infinite loop during exception

In current implementation, any exception would trigger a CPU reset.
But a bad written SPL would cause infinite loop where the system
will reload the same SPL instead of loading factory safe image.

Hence this patch is to ensure any exception will cause a hang. At this
moment, watchdog shall be triggered and Remote System Update mechanism
shall load the next production image or factory safe image.

Signed-off-by: Chin Liang See <chin.liang.see@intel.com>
Signed-off-by: Chee Hong Ang <chee.hong.ang@intel.com>
Reviewed-by: Ley Foon Tan <ley.foon.tan@intel.com>