arch: arm: cortex_m: z_arm_pendsv in vector table when multithreading
arch: arm: cortex_m: z_arm_pendsv in vector table when multithreading

When CONFIG_MULTITHREADING=n kernel specific pendsv is not used. Remove
from vector table.

Signed-off-by: Krzysztof Chruscinski <9b6dc988558c51b0405b49b55c8e66862969844b@nordicsemi.no>

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