NFC: Fix LLCP TLV building routine

The if logic could lead to zero length TLVs.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/nfc/llcp/commands.c b/net/nfc/llcp/commands.c
index 4aa52b8b..34ee684 100644
--- a/net/nfc/llcp/commands.c
+++ b/net/nfc/llcp/commands.c
@@ -102,7 +102,7 @@
 	length = llcp_tlv_length[type];
 	if (length == 0 && value_length == 0)
 		return NULL;
-	else
+	else if (length == 0)
 		length = value_length;
 
 	*tlv_length = 2 + length;