Initialize DMA memcpy config struct

Call `dma_multi_data_para_struct_init(&dma_init_parameter)` before assigning selected fields in `gd32_dma_memcpy32.cpp`. This ensures all DMA config fields start from defined defaults and prevents unintended behavior from uninitialized struct members.

Author: vanvught

lib-gd32/src/f/gd32_dma_memcpy32.cpp

@@ -57,6 +57,7 @@ void Init() {
     dma_deinit(DMA1, DMA_CH0);
 
     dma_multi_data_parameter_struct dma_init_parameter;
+    dma_multi_data_para_struct_init(&dma_init_parameter);
 
     dma_init_parameter.periph_width = DMA_PERIPH_WIDTH_32BIT;
     dma_init_parameter.periph_inc = DMA_PERIPH_INCREASE_ENABLE;