Bluetooth: Audio: Fix CSIP compliance check with returns after else
Bluetooth: Audio: Fix CSIP compliance check with returns after else

The compliance check did not like the otherwise valid
way of returning from read_set_sirk.

The code has been slightly refactored to avoid the check
failing in CI.

Signed-off-by: Emil Gydesen <a20314356615223738233ab4c4eb1cd8cd4146fa@nordicsemi.no>

zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr