Hi guys .. it might be late to answer this but I will explain the best way (as I can see)
first, u should use (extract by mask) which is one of the tool in ArcGIS where u can mask the first layer (i.e.LULC) using (LST) or vise versa
After finishing the masking, u can check in the properties that both layers have the same number of row and columns.
Second, use (raster to ASCII) tool which also available in ArcGIS to convert both layers into text format then open both of them using notepad or any other alternative program (I prefer Editpad Lite) and delete the header of them
Note: the header file can also show u the number of rows and columns of the resulted image.
Third, from file menu in SPSS, click on read text file and just click next until the part where u should define the number of columns where u should choose 1
do this process to the both layers then apply LR or any other algorithm u like to use.