fix(export): write_perm: unit conversion for default_perm

Author: djmaxus

src/export/common/write_perm.m

@@ -1,10 +1,11 @@
 function write_perm(prefix,G,perm,idx,default_perm)
-perm = perm / milli / darcy;
+perm_mD = perm / milli / darcy;
 perm_mapping = zeros(prod(G.cartDims),3);
 if ~isempty(default_perm)
-    perm_mapping(:,:) = default_perm;
+    default_perm_mD = default_perm / milli / darcy;
+    perm_mapping(:,:) = default_perm_mD;
 end
-perm_mapping(G.cells.indexMap(idx),:) = perm;
+perm_mapping(G.cells.indexMap(idx),:) = perm_mD;
 keywords = ["PERMX","PERMY","PERMZ"];
 for keyword_num = 1:length(keywords)
     keyword = keywords(keyword_num);