kernel: prioritize C atomic functions if selected
kernel: prioritize C atomic functions if selected

Usually, GCC builtin or arch-specific atomic functions are being
used. The corresponding kconfigs are "selected" by architecture
or SoC kconfigs. CONFIG_ATOMIC_OPERATIONS_C is usually used to
override the GCC built-in or arch-specific atomic functions when
these two are not supported. So change the priority of #include
so that C version is included first if selected, and skips
the inline versions of the other two variants. Or else there
will be two compiled versions of atomic functions: inline version
and the compiled C version. Note that the arch-specific version
and builtin are swapped, so the builtin one is now the default.

Fixes #33857

Signed-off-by: Daniel Leung <d94e04d205b5962d7873a139ef298b03c1717f72@intel.com>

galak/zephyr,Vudentz/zephyr,galak/zephyr,nashif/zephyr,finikorg/zephyr,nashif/zephyr,Vudentz/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,Vudentz/zephyr,nashif/zephyr,Vudentz/zephyr,galak/zephyr,galak/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,Vudentz/zephyr,Vudentz/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr