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/toolchain/p8-pore-toolchain/Config.in b/openpower/toolchain/p8-pore-toolchain/Config.in
new file mode 100644
index 0000000..40dd48d
--- /dev/null
+++ b/openpower/toolchain/p8-pore-toolchain/Config.in
@@ -0,0 +1,6 @@
+config BR2_PACKAGE_HAS_P8_PORE_TOOLCHAIN
+	bool
+
+config BR2_PACKAGE_PROVIDES_P8_PORE_TOOLCHAIN
+	depends on BR2_PACKAGE_HAS_P8_PORE_TOOLCHAIN
+	string