atftp: add new package

TODO:
	- add init script for atftpd
	- merge '120-retry-option.patch' from old atftp packages.

Signed-off-by: Daniel Danzberger <daniel@dd-wrt.com>

net/atftp/patches/01-missing-u_char-type-patch.patch

@@ -0,0 +1,13 @@
+diff --git a/tftpd.h b/tftpd.h
+index 945065e..4c2f214 100644
+--- a/tftpd.h
++++ b/tftpd.h
+@@ -46,7 +46,7 @@ struct thread_data {
+      char *mc_addr;             /* multicast address */
+      struct sockaddr_storage sa_mcast;
+      union ip_mreq_storage mcastaddr;
+-     u_char mcast_ttl;
++     unsigned char mcast_ttl;
+      
+      /*
+       * Self can read/write until client_ready is set. Then only allowed to read.