Portenta C33: Msd QSPI examples, mount both partition

[pennam]

By default Portenta C33 QSPI flash is partitioned with this scheme

ArduinoCore-renesas/libraries/Storage/examples/QSPIFormat/QSPIFormat.ino

Lines 55 to 56 in b82e642

	MBRBlockDevice::partition(root, 1, 0x0B, 0, 5 * 1024 * 1024);
	MBRBlockDevice::partition(root, 2, 0x0B, 5 * 1024 * 1024, 16 * 1024 * 1024);

With this changes both partitions are mounted as mass storage. If user partition is formatted as LittleFS it will be skipped.