Bluetooth: Audio: Media control - add const keyword
Bluetooth: Audio: Media control - add const keyword

Add const keyword to variables that shall not change their value.

Signed-off-by: Asbjørn Sæbø <79238bdce2d54e50328756ad5a8d04b51bb621fe@nordicsemi.no>

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