Remove WATCHDOG from TARGET_SEQUANA
Remove WATCHDOG from TARGET_SEQUANA

This was added to TARGET_PSOC6 which TARGET_SEQUANA inherits from,
but TARGET_SEQUANA doesn't implement WATCHDOG

kjbracey-arm/mbed,andcor02/mbed-os,mbedmicro/mbed,andcor02/mbed-os,mbedmicro/mbed,andcor02/mbed-os,andcor02/mbed-os,mbedmicro/mbed,kjbracey-arm/mbed,mbedmicro/mbed,mbedmicro/mbed,kjbracey-arm/mbed,andcor02/mbed-os,andcor02/mbed-os,kjbracey-arm/mbed