Update to buildroot 2016.05

 - package/dropbear: Add BR2_PACKAGE_DROPBEAR_SERVER option
 - host-fakeroot: re-run autotools to fix build on ppc64le host
 - linux-firmware: Update bnx2x firmware version

Configuration changes:

 - BR2_BINUTILS_VERSION_2_26_X selects the most modern version
 - BR2_LINUX_KERNEL_CUSTOM_VERSION replaces LATEST_VERSION as upstream
   tracks a newer version than we are using
 - BR2_PACKAGE_SKIBOOT is default y if (BR2_OPENPOWER_PLATFORM && BR2_powerpc_power8)
   BR2_PACKAGE_POWERPC_UTILS is selected by petitboot
 - The BR2_TOOLCHAIN_BUILDROOT_LIBSTDCPP symbol was never upstreamed.
   It's implemented by BR2_INSTALL_LIBSTDCPP in upstream, and we don't
   have it enabled.

Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/openpower/configs/openpower_mambo_defconfig b/openpower/configs/openpower_mambo_defconfig
index c7ba28e..c006db4 100644
--- a/openpower/configs/openpower_mambo_defconfig
+++ b/openpower/configs/openpower_mambo_defconfig
@@ -20,10 +20,6 @@
 
 BR2_TARGET_GENERIC_HOSTNAME="skiroot"
 
-# skiboot will be built but we don't need embedded payload
-BR2_PACKAGE_SKIBOOT=y
-BR2_PACKAGE_SKIBOOT_EMBED_PAYLOAD=n
-
 # petitboot requirements
 BR2_ENABLE_LOCALE_PURGE=y
 BR2_ENABLE_LOCALE_WHITELIST="C en_US"
@@ -34,8 +30,10 @@
 BR2_ROOTFS_DEVICE_TABLE="../openpower/device_table.txt"
 BR2_ROOTFS_POST_BUILD_SCRIPT="../openpower/scripts/fixup-target-var"
 BR2_LINUX_KERNEL=y
-BR2_LINUX_KERNEL_LATEST_VERSION=y
+BR2_LINUX_KERNEL_CUSTOM_VERSION=y
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.4.13"
 BR2_KERNEL_HEADERS_4_4=y
+BR2_BINUTILS_VERSION_2_26_X=y
 BR2_LINUX_KERNEL_PATCH="$(BR2_EXTERNAL)/linux"
 BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
 BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="$(BR2_EXTERNAL)/configs/linux/skiroot_defconfig"
@@ -53,7 +51,6 @@
 BR2_PACKAGE_RSYNC=y
 BR2_PACKAGE_PETITBOOT=y
 BR2_PACKAGE_IPMITOOL=y
-BR2_PACKAGE_POWERPC_UTILS=y
 BR2_PACKAGE_MDADM=y
 BR2_TARGET_ROOTFS_CPIO_XZ=y
 BR2_TARGET_ROOTFS_INITRAMFS=y