Create virtual packages for OpenPower toolchain

Create a "toolchain" category, plus "p8-pore-toolchain" and
"ppe42-toolchain" virtual-packages, with the goal of lowering the
coupling between these toolchain and target packages.

Signed-off-by: Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com>
diff --git a/openpower/package/p8-pore-binutils/Config.in b/openpower/package/p8-pore-binutils/Config.in
index a29397a..3d69782 100644
--- a/openpower/package/p8-pore-binutils/Config.in
+++ b/openpower/package/p8-pore-binutils/Config.in
@@ -1,6 +1,12 @@
 config BR2_PACKAGE_HOST_P8_PORE_BINUTILS
         bool "p8-pore-binutils"
         default y if (BR2_OPENPOWER_POWER8)
+        select BR2_PACKAGE_HAS_P8_PORE_TOOLCHAIN
         select BR2_CPP
         help
             Project to build the P8 PORE binutils
+
+if BR2_PACKAGE_HOST_P8_PORE_BINUTILS
+config BR2_PACKAGE_PROVIDES_P8_PORE_TOOLCHAIN
+        default "p8-pore-binutils"
+endif