Only use LSI crystal

Author: pennam

targets/TARGET_STM/TARGET_STM32H7/TARGET_STM32H747xI/TARGET_PORTENTA_H7/COMPONENT_WHD/resources/nvram/TARGET_STM32H747xI/wifi_nvram_image.h

@@ -49,7 +49,7 @@ static const char wifi_nvram_image[] =
         NVRAM_GENERATED_MAC_ADDRESS             "\x00"
         "sromrev=11"                            "\x00"
         "boardflags=0x00404201"                 "\x00"
-        "boardflags3=0x08000000"                "\x00"
+        "boardflags3=0x04000000"                "\x00"
         "xtalfreq=37400"                        "\x00"
         "nocrc=1"                               "\x00"
         "ag0=0"                                 "\x00"