Enable ppe42-{gcc,binutils} as external toolchain

Create the infrastructure necessary to bundle ppe42-gcc and
ppe42-binutils as part of the sdk build, allowing it to be
re-inserted as part of an external sdk.

Signed-off-by: Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com>
diff --git a/openpower/package/ppe42-gcc/ppe42-gcc.mk b/openpower/package/ppe42-gcc/ppe42-gcc.mk
index a59071d..8aa73ce 100644
--- a/openpower/package/ppe42-gcc/ppe42-gcc.mk
+++ b/openpower/package/ppe42-gcc/ppe42-gcc.mk
@@ -12,8 +12,8 @@
 HOST_PPE42_GCC_DEPENDENCIES = host-ppe42-binutils host-gmp host-mpfr host-mpc
 PPE42_GCC_PROVIDES = ppe42-toolchain
 
-PPE42_GCC_DIR = $(STAGING_DIR)/ppe42-binutils
-PPE42_GCC_BIN = $(STAGING_DIR)/ppe42-binutils/linux
+PPE42_GCC_DIR = $(HOST_DIR)/$(PPE42_TOOLCHAIN_DIR)
+PPE42_GCC_BIN = $(HOST_DIR)/$(PPE42_TOOLCHAIN_BIN)
 
 define HOST_PPE42_GCC_BUILD_CMDS
         cd $(@D) && \