- Make the Create*Partition helpers take a size in bytes, not in sectors.
This allows them to be easier to use by the caller, alleviating the
need for making the size conversion into sectors. Instead it is done
internally by the helpers.
- Introduce helper macros to easily retrieve the size of a partition
entry or a disk in bytes, from their internal representation in number
of sectors.
- The 'AutoCreate' variable being USETUP-specific, remove it from the
PARTENTRY structure and use instead a flag set into the 'New' member.
- Rename IsDiskSizeValid to IsPartitionLargeEnough, to better describe
what the function is for.