buildroot: Move to 2017.05 release

The following packages have been updated since buildroot 2017.02.2:

 lvm2: 2.02.168 -> 2.02.170
 check: 0.10.0 -> 0.11.0
 kmod: 23 -> 24
 powerpc-utils: v1.3.1 -> v1.3.3
 glibc: 2.24 -> 2.25
 dropbear: 2016.74 -> 2017.75
 ethtool: 4.8 -> 4.10
 ncurses: 5.9 -> 6.0
 eudev: 3.2.1 -> 3.2.2
 dtc: 1.4.1 -> 1.4.4
 elfutils: 0.166 -> 0.169

In addition, merge the 2017.05.x stable branch to bring in a build fix
for kmod.

Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/openpower/configs/firenze_defconfig b/openpower/configs/firenze_defconfig
index b079318..d538a80 100644
--- a/openpower/configs/firenze_defconfig
+++ b/openpower/configs/firenze_defconfig
@@ -1,7 +1,7 @@
 BR2_powerpc64le=y
 BR2_powerpc_power8=y
-BR2_GLIBC_VERSION_2_24=y
-BR2_BINUTILS_VERSION_2_27_X=y
+BR2_GLIBC_VERSION_2_25=y
+BR2_BINUTILS_VERSION_2_28_X=y
 BR2_BINUTILS_EXTRA_CONFIG_OPTIONS="--enable-targets=powerpc64-linux"
 BR2_GCC_VERSION_6_X=y
 BR2_EXTRA_GCC_CONFIG_OPTIONS="--enable-targets=powerpc64-linux"