tftp: fix thinko in code shrink

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/tftp.c b/networking/tftp.c
index 4d608a6..043747d 100644
--- a/networking/tftp.c
+++ b/networking/tftp.c
@@ -466,7 +466,7 @@
 		}
 		cp = stpcpy(cp, remote_file) + 1;
 		/* add "mode" part of the packet */
-		cp = stpcpy(cp, "octet");
+		cp = stpcpy(cp, "octet") + 1;
 
 # if ENABLE_FEATURE_TFTP_BLOCKSIZE
 		if (blksize == TFTP_BLKSIZE_DEFAULT && !want_transfer_size)