init: initialize dummy thread stack info
init: initialize dummy thread stack info

Garbage values here could wreak havoc on the initial switch to main
depending on how arch-specific _Swap() manages memory permissions when
switching threads.

Signed-off-by: Andrew Boie <aab045b28152628be6af0e556050d0381fd0a34d@intel.com>

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