mbed::MBRBlockDevice::partition wrong size when using QSPIFBlockDevice

on the arduino giga, using the method :
partition(BlockDevice *bd, int part, uint8_t type, bd_addr_t start);

which states that:
This is the same as partition(bd, part, type, start**, bd->size(**))

a partition is created that is many times larger than the BD size. Looking at the partition table, that partition was like 16TB instead of MB if I remember correctly. I guess that the QSPIFBlockDevice returns its size on a way that is not interpreted correctly by partition.

Trying to access that partition made the arduino to hang. I ended fixing the partition using an external device.

Start by reproducing the issue on the Arduino GIGA with QSPIFBlockDevice and the mbed::MBRBlockDevice::partition(BlockDevice *bd, int part, uint8_t type, bd_addr_t start) overload. Compare the partition-table size with bd->size(); done means the partition size matches the block device and accessing it no longer hangs.

Written by the indexing model from the issue text.