vvfat: reorganize computation of disk geometry First determine FAT12/16/32, then compute geometry from that for both FDD and HDD. For 1.44MB floppies, and 2.88MB floppies using FAT16, change to 1 sector/cluster. The default remains 2.88MB with FAT12 and 2 sectors/cluster. Both DOS and mkdosfs by default format a 2.88MB floppy as FAT12. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>