[M487] Add dma_modbase() to get PDMA base address

targets/TARGET_NUVOTON/TARGET_M480/dma.h

@@ -32,6 +32,7 @@ extern "C" {
 #define DMA_EVENT_MASK              DMA_EVENT_ALL
 
 void dma_set_handler(int channelid, uint32_t handler, uint32_t id, uint32_t event);
+PDMA_T *dma_modbase(void);
 
 #ifdef __cplusplus
 }

targets/TARGET_NUVOTON/TARGET_M480/dma_api.c

@@ -111,6 +111,11 @@ void dma_set_handler(int channelid, uint32_t handler, uint32_t id, uint32_t even
     NVIC_EnableIRQ(dma_modinit.irq_n);
 }
 
+PDMA_T *dma_modbase(void)
+{
+    return (PDMA_T *) NU_MODBASE(dma_modinit.modname);
+}
+
 static void pdma_vec(void)
 {
     uint32_t intsts = PDMA_GET_INT_STATUS();