gtDefDmvol2Gvdm: modified to adapt to various input size

Signed-off-by: preischig <preischig@gmail.com>

zUtil_Deformation/gtDefDmvol2Gvdm.m

 function [gvdm, dmvol_size] = gtDefDmvol2Gvdm(dmvol)
     [dmvol_size(1), dmvol_size(2), dmvol_size(3), dmvol_size(4)] = size(dmvol);
     gvdm = permute(dmvol, [4 1 2 3]);
-    gvdm = reshape(gvdm, 3, []);
+    gvdm = reshape(gvdm, dmvol_size(4), []);
 end
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