drivers: usb: device_stm32: Update USB_DC speed macros

Updated USB_DC speed definition macros for STM32 series
to handle different speed configurations
based on the SoC compatibility.

Added conditional checks for full-speed definitions
using DT_HAS_COMPAT_STATUS_OKAY for st_stm32_usb.

Signed-off-by: Khaoula Bidani <khaoula.bidani-ext@st.com>
Signed-off-by: IBEN EL HADJ MESSAOUD Marwa <marwa.ibenelhadjmessaoud-ext@st.com>