HAL_ChibiOS: H7 doesn't need a DMA mapping for SDMMC

it uses a dedicated internal DMA controller in the SDMMC peripheral

libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py

@@ -1349,6 +1349,7 @@ def build_peripheral_list():
         if type.startswith('ADC'):
             peripherals.append(type)
         if type.startswith('SDIO') or type.startswith('SDMMC'):
+            if not mcu_series.startswith("STM32H7"):
                 peripherals.append(type)
         if type.startswith('TIM'):
             if p.has_extra('RCIN'):