arm64: Build infrastructure

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

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/init/Kconfig b/init/Kconfig
index af6c7f8..8bfda46 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1153,7 +1153,8 @@
 
 config UID16
 	bool "Enable 16-bit UID system calls" if EXPERT
-	depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION)
+	depends on ARM || BLACKFIN || CRIS || FRV || H8300 || X86_32 || M68K || (S390 && !64BIT) || SUPERH || SPARC32 || (SPARC64 && COMPAT) || UML || (X86_64 && IA32_EMULATION) \
+		|| AARCH32_EMULATION
 	default y
 	help
 	  This enables the legacy 16-bit UID syscall wrappers.