super-intel: make freesize not required for chunk size migration

super-intel: make freesize not required for chunk size migration

Freesize is needed to be set for migrations where size of RAID could
be changed - expand. It tells how many free space is determined for
members. In chunk size migartion freesize is not needed to be set,
pointer shouldn't be checked if exists. This commit moves check to
condition which contains size calculations, instead of checking it
always at the first step.
Fix return value when superblock is not set.

Signed-off-by: Kinga Tanska <kinga.tanska@intel.com>
Signed-off-by: Jes Sorensen <jes@trained-monkey.org>