subsys: logging: Fix switch statement
subsys: logging: Fix switch statement

According with MISRA-C and unconditional break statement must
terminate every switch-clause.

MISRA-C rule 16.1 and 16.3

Signed-off-by: Flavio Ceolin <979b9165500b0741b9d0500e2efd74fc1547bff7@intel.com>

finikorg/zephyr,galak/zephyr,punitvara/zephyr,galak/zephyr,punitvara/zephyr,nashif/zephyr,finikorg/zephyr,punitvara/zephyr,nashif/zephyr,galak/zephyr,explora26/zephyr,finikorg/zephyr,explora26/zephyr,ldts/zephyr,punitvara/zephyr,GiulianoFranchetto/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,Vudentz/zephyr,finikorg/zephyr,ldts/zephyr,nashif/zephyr,explora26/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,Vudentz/zephyr,ldts/zephyr,finikorg/zephyr,nashif/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,punitvara/zephyr,Vudentz/zephyr,Vudentz/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr