support/config-fragments: update ARC pre-built toolchain

This is needed to get the autobuilders to use a toolchain that
includes the fix merged in 9d544feb8a277a43abec889450f917017d666e49
("fwup: fix for ARC toolchain").

In addition, this new toolchain version also fixes for real the RPATH
issue that should have been fixed by
f90f28a6dfe85439d11e5fd83f2462ff29502e11, but wasn't done properly.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

support/config-fragments/autobuild/br-arcle-hs38.config

@@ -3,7 +3,7 @@ BR2_archs38=y
 BR2_TOOLCHAIN_EXTERNAL=y
 BR2_TOOLCHAIN_EXTERNAL_CUSTOM=y
 BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD=y
-BR2_TOOLCHAIN_EXTERNAL_URL="http://autobuild.buildroot.org/toolchains/tarballs/br-arcle-hs38-full-2017.11-rc1.1.tar.bz2"
+BR2_TOOLCHAIN_EXTERNAL_URL="http://autobuild.buildroot.org/toolchains/tarballs/br-arcle-hs38-full-2017.11-rc2-15-g9d544fe.tar.bz2"
 BR2_TOOLCHAIN_EXTERNAL_GCC_7=y
 BR2_TOOLCHAIN_EXTERNAL_HEADERS_4_1=y
 BR2_TOOLCHAIN_EXTERNAL_LOCALE=y