modules: update SOF module to latest upstream
modules: update SOF module to latest upstream

Update to 551bb2d95 of SOF tree which has few relevant bug fixes.

Signed-off-by: Anas Nashif <0d9952ec84ac43c159f6b7e7ed99a9080c00dd6e@intel.com>

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