amd64: Factorise code to make a store node depending on the mode of the value to store.
amd64: Factorise code to make a store node depending on the mode of the value to store.

jonashaag/libfirm,libfirm/libfirm,jonashaag/libfirm,jonashaag/libfirm,jonashaag/libfirm,MatzeB/libfirm,libfirm/libfirm,MatzeB/libfirm,MatzeB/libfirm,libfirm/libfirm,jonashaag/libfirm,libfirm/libfirm,jonashaag/libfirm,jonashaag/libfirm,MatzeB/libfirm,libfirm/libfirm,MatzeB/libfirm,MatzeB/libfirm,MatzeB/libfirm