ryu: update kernel prebuilt
am: 598f1832c3

Change-Id: Ia78f42e34fd7f5a9af1e9453ed7e735a165ac1f4
tree: 0ad4cdde191e9090cee87423aeca96803290235e
  1. Image.fit
  2. Image.fit.kasan
  3. push-kernel.sh