arc: Add option for ARC-specific download site

As ARC support is not yet in all upstream packages, a different location is
required to download the packages from. This adds an option to specify a
site for ARC-specific versions of packages such as binutils, gcc.

When ARC support has been upstreamed for all packages, this option can be
removed again.

Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
diff --git a/arch/Config.in.arc b/arch/Config.in.arc
index 60b59f0..9f68b46 100644
--- a/arch/Config.in.arc
+++ b/arch/Config.in.arc
@@ -12,3 +12,7 @@
 
 config BR2_GCC_TARGET_CPU
 	default "arc700"
+
+config BR2_ARC_SITE
+	string
+	default "http://www.synopsys.com/apps/arc-developer/"