COMP: N4ITKBiasFieldCorrection - Fix compilation error with ITK_USE_64BITS_IDS

Similar to the change to vtkITK applied in previous commit (r23714), this
commit fixes the build error happening on windows when building
the CLI module N4ITKBiasFieldCorrection with the option ITK_USE_64BITS_IDS
enabled.

From: Gib Bogle <g.bogle@auckland.ac.nz>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@23715 3bd1e089-480b-0410-8dfb-8563597acbee