random: Correct Mutex define

Correct Mutex ctr_lock defination as the wrong defination lead to
sysworkq task not acquiring this mutex during bt init, which lead to
BLE didn't work as described in issue https://github.com/zephyrproject-rtos/zephyr/issues/86444



Signed-off-by: Ying Zhang <ying.zhang_2@nxp.com>