Change Linux branch to 3.18 from 3.13

Signed-off-by: Anton Kolesov <[email protected]>

Author: anthony-kolesov

config/arc-dev.sh

@@ -4,4 +4,4 @@ gcc=gcc:arc-4.8-dev
 gdb=gdb:arc-7.9-dev
 newlib=newlib:arc-2.0-dev
 uclibc=uClibc:arc-mainline-dev
-linux=linux:arc-3.13
+linux=linux:arc-3.18