cinap: fix leak in libsec ecc

Reference: /n/atom/patch/applied/eccleak
Date: Thu Sep 24 04:46:21 CES 2015
Signed-off-by: quanstro@quanstro.net

--- /sys/src/libsec/port/ecc.c	Thu Sep 24 04:46:13 2015
+++ /sys/src/libsec/port/ecc.c	Thu Sep 24 04:46:14 2015
@@ -123,6 +123,7 @@
 	mpfree(ns.y);
 	mpfree(na.x);
 	mpfree(na.y);
+	mpfree(l);
 }
 
 int