dts: bindings: dma: introduce a new type of DMA
dts: bindings: dma: introduce a new type of DMA

This commit defines a new dma version for devices like stm32U5.
The peripheral is a GPDMA in this soc serie.
It has several specific definitions used by its stm32 LL driver
compared to the V2, including up to 16 channels.

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

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