arch: arm: refactor FAULT_DUMP to retrieve the fatal error reason
arch: arm: refactor FAULT_DUMP to retrieve the fatal error reason

Refactor FAULT_DUMP macro to obtain and store the fatal error
reason. Make non-default version of FAULT_DUMP (i.e. with
CONFIG_FAULT_DUMP level 1) to retrieve the default reason
for fatal errors (_NANO_ERR_HW_EXCEPTION).

Signed-off-by: Ioannis Glaropoulos <5921cc8bab7e1d4329f52fd8f6268f9692e3de80@nordicsemi.no>

nashif/zephyr,kraj/zephyr,mbolivar/zephyr,mbolivar/zephyr,mbolivar/zephyr,zephyrproject-rtos/zephyr,kraj/zephyr,kraj/zephyr,zephyrproject-rtos/zephyr,zephyriot/zephyr,finikorg/zephyr,punitvara/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,mbolivar/zephyr,zephyrproject-rtos/zephyr,punitvara/zephyr,ldts/zephyr,mbolivar/zephyr,explora26/zephyr,galak/zephyr,finikorg/zephyr,Vudentz/zephyr,ldts/zephyr,punitvara/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,explora26/zephyr,finikorg/zephyr,nashif/zephyr,ldts/zephyr,zephyriot/zephyr,nashif/zephyr,galak/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,punitvara/zephyr,Vudentz/zephyr,ldts/zephyr,finikorg/zephyr,kraj/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,Vudentz/zephyr,zephyriot/zephyr,zephyriot/zephyr,explora26/zephyr,explora26/zephyr,explora26/zephyr,zephyriot/zephyr,Vudentz/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,nashif/zephyr,punitvara/zephyr,galak/zephyr,kraj/zephyr