This patch adds Makefile and Kconfig files required for building an
AArch64 kernel.

Signed-off-by: Will Deacon
Signed-off-by: Catalin Marinas
Acked-by: Tony Lindgren
Acked-by: Nicolas Pitre
Acked-by: Olof Johansson
Acked-by: Santosh Shilimkar
Acked-by: Arnd Bergmann