arch: x86: Kconfig: Fix CACHE_LINE_SIZE default for CPU_ATOM
arch: x86: Kconfig: Fix CACHE_LINE_SIZE default for CPU_ATOM

With Zephyr's prefer-later-defaults behavior, the default value of
CACHE_LINE_SIZE was always 0, because 'default 0' acts like
'default 0 if y'.

Change the code to what was probably the intention (default to 0 unless
CPU_ATOM).

It looks like CACHE_LINE_SIZE is never used in the code when
CACHE_LINE_SIZE_DETECT is on, so maybe things could be simplified
further.

Piggy-back some prompt style consistency cleanups.

Signed-off-by: Ulf Magnusson <01743f1c1deb1fe75271d62edb65757d98ac0bcb@nordicsemi.no>

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