stm32/boards/ARDUINO_PORTENTA_H7: Update board config files.

Changes are:
- Freeze micropython-lib time module to get strftime.
- Reserve the last 1MB of QSPI flash for (optional) WiFi firmware storage.
- Disable SD card mount on boot.
- Enable high-speed BLE firmware download.

ports/stm32/boards/ARDUINO_PORTENTA_H7/manifest.py

@@ -4,6 +4,7 @@
 require("bundle-networking")
 
 # Utils
+require("time")
 require("logging")
 
 # Bluetooth

ports/stm32/boards/ARDUINO_PORTENTA_H7/mpconfigboard.h

@@ -120,7 +120,8 @@ void PORTENTA_board_osc_enable(int enable);
 // QSPI flash #1 for storage
 #define MICROPY_HW_QSPI_PRESCALER           (2) // 100MHz
 #define MICROPY_HW_QSPIFLASH_SIZE_BITS_LOG2 (27)
-#define MICROPY_HW_SPIFLASH_SIZE_BITS       (128 * 1024 * 1024)
+// Reserve 1MiB at the end for compatibility with alternate firmware that places WiFi blob here.
+#define MICROPY_HW_SPIFLASH_SIZE_BITS       (120 * 1024 * 1024)
 #define MICROPY_HW_QSPIFLASH_CS             (pyb_pin_QSPI2_CS)
 #define MICROPY_HW_QSPIFLASH_SCK            (pyb_pin_QSPI2_CLK)
 #define MICROPY_HW_QSPIFLASH_IO0            (pyb_pin_QSPI2_D0)
@@ -203,6 +204,7 @@ extern struct _spi_bdev_t spi_bdev;
 #define MICROPY_HW_SDCARD_D1        (pin_B15)
 #define MICROPY_HW_SDCARD_D2        (pin_B3)
 #define MICROPY_HW_SDCARD_D3        (pin_B4)
+#define MICROPY_HW_SDCARD_MOUNT_AT_BOOT (0)
 
 // USB config
 #define MICROPY_HW_USB_HS           (1)
@@ -220,6 +222,7 @@ extern struct _spi_bdev_t spi_bdev;
 #define MICROPY_HW_BLE_UART_ID              (PYB_UART_7)
 #define MICROPY_HW_BLE_UART_BAUDRATE        (115200)
 #define MICROPY_HW_BLE_UART_BAUDRATE_SECONDARY (3000000)
+#define MICROPY_HW_BLE_UART_BAUDRATE_DOWNLOAD_FIRMWARE (3000000)
 
 // SDRAM
 #define MICROPY_HW_SDRAM_SIZE               (64 / 8 * 1024 * 1024)  // 64 Mbit