libpng: security bump to version 1.4.12

Fixes CVE-2012-3386

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/libpng/libpng.mk

@@ -4,7 +4,7 @@
 #
 #############################################################
 
-LIBPNG_VERSION = 1.4.11
+LIBPNG_VERSION = 1.4.12
 LIBPNG_SERIES = 14
 LIBPNG_SITE = http://$(BR2_SOURCEFORGE_MIRROR).dl.sourceforge.net/project/libpng/libpng$(LIBPNG_SERIES)/$(LIBPNG_VERSION)
 LIBPNG_SOURCE = libpng-$(LIBPNG_VERSION).tar.bz2