ovmf: Fix build with gcc7

backport a patch which fixing warnings with gcc7

(From OE-Core rev: 9c75151116aa293dc8567c237d7e4da5bdec90e3)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
(cherry picked from commit 74fb6043f6d74b84f7efc282ac6cfc54fcb71882)
Fixed up patch to apply agains this version
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/ovmf/ovmf/0001-MdeModulePkg-UefiHiiLib-Fix-incorrect-comparison-exp.patch

@@ -0,0 +1,39 @@
+From 73692710d50da1f421b0e6ddff784ca3135389b3 Mon Sep 17 00:00:00 2001
+From: Dandan Bi <dandan.bi@intel.com>
+Date: Sat, 1 Apr 2017 10:31:14 +0800
+Subject: [PATCH] MdeModulePkg/UefiHiiLib:Fix incorrect comparison expression
+
+Fix the incorrect comparison between pointer and constant zero character.
+
+https://bugzilla.tianocore.org/show_bug.cgi?id=416
+
+V2: The pointer StringPtr points to a string returned
+by ExtractConfig/ExportConfig, if it is NULL, function
+InternalHiiIfrValueAction will return FALSE. So in
+current usage model, the StringPtr can not be NULL before
+using it, so we can add ASSERT here.
+
+Cc: Eric Dong <eric.dong@intel.com>
+Cc: Liming Gao <liming.gao@intel.com>
+Contributed-under: TianoCore Contribution Agreement 1.0
+Signed-off-by: Dandan Bi <dandan.bi@intel.com>
+Reviewed-by: Eric Dong <eric.dong@intel.com>
+---
+Upstream-Status: Backport
+
+ MdeModulePkg/Library/UefiHiiLib/HiiLib.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+Index: git/MdeModulePkg/Library/UefiHiiLib/HiiLib.c
+===================================================================
+--- git.orig/MdeModulePkg/Library/UefiHiiLib/HiiLib.c
++++ git/MdeModulePkg/Library/UefiHiiLib/HiiLib.c
+@@ -2180,6 +2180,8 @@ InternalHiiIfrValueAction (
+   }
+   
+   StringPtr = ConfigAltResp;
++
++  ASSERT (StringPtr != NULL);
+   
+   while (StringPtr != L'\0') {
+     //

meta/recipes-core/ovmf/ovmf_git.bb

@@ -14,6 +14,7 @@ SRC_URI = "git://github.com/tianocore/edk2.git;branch=master \
 	file://0002-ovmf-update-path-to-native-BaseTools.patch \
 	file://0003-BaseTools-makefile-adjust-to-build-in-under-bitbake.patch \
 	file://VfrCompile-increase-path-length-limit.patch \
+        file://0001-MdeModulePkg-UefiHiiLib-Fix-incorrect-comparison-exp.patch \
         "
 
 SRC_URI_append_class-target = " \