Allow unlock_udc for all serial addresses

[gabrielbrunheira]

PS Models like FAC_2P4S_DCDC work with more than one BSMP server, hence, more than one serial address on the RS-485 interface. However, the unlock_udc() function only works with the first one, specified by parameter RS485_Address[0].

This may confuse an operator trying to set new parameters while communicating with one of the other addresses. Fix this, allowing all active serial addresses to unlock the board.