dts: arm: stm32l5 Invalid wwdg interrupt priority
dts: arm: stm32l5 Invalid wwdg interrupt priority

Set the priority of the wwdg instance to 6
else a build error happens :
static assertion failed: "Invalid interrupt priority.
Values must not exceed IRQ_PRIO_LOWEST"

Signed-off-by: Francois Ramu <b83adc7f8a23ee911a37fcb61c4033581aae0b7a@st.com>

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