ARM: make LTO available

Make LTO available for ARM architecture.

Signed-off-by: Marek BehĂșn <marek.behun@nic.cz>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/Kconfig b/arch/Kconfig
index 8fd39e3..49813a4 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -33,6 +33,7 @@
 
 config ARM
 	bool "ARM architecture"
+	select ARCH_SUPPORTS_LTO
 	select CREATE_ARCH_SYMLINK
 	select HAVE_PRIVATE_LIBGCC if !ARM64
 	select SUPPORT_OF_CONTROL