Mark AArch64 as a 64 bits architecture

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

arch/Config.in

@@ -25,6 +25,7 @@ config BR2_armeb
 
 config BR2_aarch64
 	bool "AArch64"
+	select BR2_ARCH_IS_64
 	help
 	  Aarch64 is a 64-bit architecture developed by ARM Holdings.
 	  http://www.arm.com/products/processors/instruction-set-architectures/armv8-architecture.php