sanitycheck: don't multiply CPU count
sanitycheck: don't multiply CPU count

We have a number of timing sensitive tests which run
correctly on a much more frequent basis if the system
is not so heavily loaded. Instead of squeezing a few
more crumbs of performance by doubling the CPU count,
just use the number of CPUs reported by the system.

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

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