Revert "x86: qemu_x86_64: workaround SMP issues in x86"
Revert "x86: qemu_x86_64: workaround SMP issues in x86"

Races seem fixed, at least the ones measurable by existing tests.

This reverts commit 3f3c72a9113213c22fcd956c832d4672876889c7.

Signed-off-by: Andy Ross <c70f9a6bf6ee0cd69c8af4ce5e6b131945769315@intel.com>

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