busybox: add 1.19.2 tftp fix

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/busybox/busybox-1.19.2/busybox-1.19.2-tftp.patch

@@ -0,0 +1,12 @@
+--- busybox-1.19.2/networking/tftp.c
++++ busybox-1.19.2-tftp/networking/tftp.c
+@@ -813,7 +813,8 @@ int tftpd_main(int argc UNUSED_PARAM, ch
+ 		goto err;
+ 	}
+ 	mode = local_file + strlen(local_file) + 1;
+-	if (mode >= block_buf + result || strcmp(mode, "octet") != 0) {
++	/* RFC 1350 says mode string is case independent */
++	if (mode >= block_buf + result || strcasecmp(mode, "octet") != 0) {
+ 		goto err;
+ 	}
+ # if ENABLE_FEATURE_TFTP_BLOCKSIZE