dts: arm: stm32g0: Add dma1, dma2, and dmamux1

STM32G0 is supported by the st,stm32-dma-v2 driver.
This commit adds dma1 and dmamux dts bindings
for stm32g03x, stm32g05x and stm32g07x.
For stm32g0bx additionally dma2 is added.

Signed-off-by: Thomas Stranger <thomas.stranger@outlook.com>