tools/expat: Update to 2.2.0

Updates expat to 2.2.0

Fixes several CVEs:
CVE-2016-0718
CVE-2016-4472
CVE-2016-5300
CVE-2012-6702

Signed-off-by: Daniel Engberg <daniel.engberg.lists@pyret.net>

tools/expat/Makefile

@@ -8,10 +8,10 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=expat
-PKG_VERSION:=2.1.0
+PKG_VERSION:=2.2.0
 
-PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
-PKG_MD5SUM:=dd7dab7a5fea97d2a6a43f511449b7cd
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
+PKG_MD5SUM:=2f47841c829facb346eb6e3fab5212e2
 PKG_SOURCE_URL:=@SF/expat
 
 HOST_BUILD_PARALLEL:=1