qemu: bump to version 2.11.1

Here are the notable changes

 - pixman is now not part of the release tarball and is required as an
   external dependency
 - archipelago is removed by upstream
 - patches are regenerated with git-format-patch
 - ifunc requirement is now removed

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

utils/qemu/patches/0001-configure-allow-disable-fortify_source.patch

@@ -0,0 +1,27 @@
+From 0b4011cd0983ced6e065f397049f967656494793 Mon Sep 17 00:00:00 2001
+From: Yousong Zhou <yszhou4tech@gmail.com>
+Date: Sat, 24 Feb 2018 13:43:19 +0800
+Subject: [PATCH 1/3] configure: allow disable fortify_source
+
+Tell build system of qemu to not add _FORTIFY_SOURCE options and let the
+OpenWrt base build system decide flavor of fortify_source to use
+---
+ configure | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/configure b/configure
+index 0c6e757..8ea3fdd 100755
+--- a/configure
++++ b/configure
+@@ -1313,6 +1313,8 @@ for opt do
+   ;;
+   --disable-git-update) git_update=no
+   ;;
++  --disable-fortify-source) fortify_source="no"
++  ;;
+   *)
+       echo "ERROR: unknown option $opt"
+       echo "Try '$0 --help' for more information"
+-- 
+1.8.3.1
+