3rdparty/arm-trusted-firmware: Update to upstream master

Submodule 3rdparty/arm-trusted-firmware 236c27d21f..3944adca59

This brings in 241 new commits from the upstream arm-trusted-firmware
repository, merged to the upstream tree between December 30, 2016 and
March 18, 2017.

3944adca Merge pull request #861 from soby-mathew/sm/aarch32_fixes
..
e0f083a0 fiptool: Prepare ground for expanding the set of images at
runtime

Also setup ATF builds so that unused functions don't break the build.
They're harmless and they don't filter for these like we do.

Change-Id: Ibf5bede79126bcbb62243808a2624d9517015920
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/18954
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
diff --git a/3rdparty/arm-trusted-firmware b/3rdparty/arm-trusted-firmware
index 236c27d..3944adc 160000
--- a/3rdparty/arm-trusted-firmware
+++ b/3rdparty/arm-trusted-firmware
@@ -1 +1 @@
-Subproject commit 236c27d21f52ad8f0a998e54774e3d8a4b59129d
+Subproject commit 3944adca5943a050ca7e7e9cc802a9ae04dec186
diff --git a/src/arch/arm64/Makefile.inc b/src/arch/arm64/Makefile.inc
index ad3941b..92b26f5 100644
--- a/src/arch/arm64/Makefile.inc
+++ b/src/arch/arm64/Makefile.inc
@@ -166,7 +166,7 @@
 # multi line string.
 BL31_MAKEARGS += BUILD_MESSAGE_TIMESTAMP='"$(shell grep "\#define COREBOOT_BUILD\>" $(obj)/build.h |cut -d\" -f2 \# \")"'
 
-BL31_CFLAGS := -fno-pic -fno-stack-protector -Wno-deprecated-declarations
+BL31_CFLAGS := -fno-pic -fno-stack-protector -Wno-deprecated-declarations -Wno-unused-function
 BL31_LDFLAGS := --emit-relocs
 
 BL31 := $(obj)/bl31.elf