arch/x86: Use Zephyr HW shadow stack arch interface

So that kernel created threads can use shadow stacks. Note that
CONFIG_X86_CET_SHADOW_STACK is abandoned in favour of
CONFIG_HW_SHADOW_STACK.

This means change some types, functions and macro throughout shadow
stack code.

Signed-off-by: Ederson de Souza <ederson.desouza@intel.com>