drivers: usb_dc_stm32: Change SYS_LOG_LEVEL
drivers: usb_dc_stm32: Change SYS_LOG_LEVEL

Suppress messages by DBG SYS_LOG_LEVEL setting:
[general] [ERR] usb_dc_ep_check_cap: ep 81, mps 64, type 2
[general] [ERR] usb_dc_ep_check_cap: ep 1, mps 64, type 2

Signed-off-by: Istvan Bisz <8b66ff549aa6abbe830a86280df712e9f5eaecdf@t-online.hu>

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