mvebu arm64 for 5.2 (part 1)

 - Update the defconfig to enable the mv-xor driver found on the
   Armada 3700

* tag 'mvebu-arm64-5.2-1' of git://git.infradead.org/linux-mvebu:
  arm64: defconfig: enable mv-xor driver
Signed-off-by: Olof Johansson <olof@lixom.net>