perl: enable threading support for aarch64 by default

Perl threads seem to be supported and working for aarch64, and
including aarch64 here would allow packages like freeswitch-mod-perl
to become available from the standard OpwnWrt package repository for
popular routers such as the Linksys E8450 and Belkin RT3200.

Signed-off-by: Doug Thomson <dwt62f+github@gmail.com>

lang/perl/Config.in

@@ -3,7 +3,7 @@ menu "Configuration"
 
 config PERL_THREADS
     bool "Enable threading support"
-    default y if (mips || mipsel || i386 || i686 || x86_64 || armeb || arm)
+    default y if (mips || mipsel || i386 || i686 || x86_64 || armeb || arm || aarch64)
     default n
 
 config PERL_TESTS