[radv] Fix Script Name Change (sonic-net#7254)

PR sonic-net#4599 changed startup
script name from wait_for_intf.sh.j2 to wait_for_link.sh.j2, however
when PR sonic-net#5178 was cherry-
picked, the script name was not changed to wait_for_link.sh.

signed-off-by: Tamer Ahmed <tamer.ahmed@microsoft.com>

dockers/docker-router-advertiser/docker-init.sh

@@ -8,10 +8,10 @@ CFGGEN_PARAMS=" \
     -d \
     -t /usr/share/sonic/templates/docker-router-advertiser.supervisord.conf.j2,/etc/supervisor/conf.d/supervisord.conf \
     -t /usr/share/sonic/templates/radvd.conf.j2,/etc/radvd.conf \
-    -t /usr/share/sonic/templates/wait_for_intf.sh.j2,/usr/bin/wait_for_intf.sh \
+    -t /usr/share/sonic/templates/wait_for_link.sh.j2,/usr/bin/wait_for_link.sh \
 "
 sonic-cfggen $CFGGEN_PARAMS
 
-chmod +x /usr/bin/wait_for_intf.sh
+chmod +x /usr/bin/wait_for_link.sh
 
 exec /usr/bin/supervisord