logging: missing func doc for param package_flags in log_msg2.h
logging: missing func doc for param package_flags in log_msg2.h

This adds the missing "@param package_flags" for
z_log_msg2_runtime_create() and z_log_msg2_runtime_vcreate().

Signed-off-by: Daniel Leung <d94e04d205b5962d7873a139ef298b03c1717f72@intel.com>

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