Single XML package rather than one per platform

This saves us a *lot* of copy&pasted build foo and replaces it with a couple
of config options that can be set in menuconfig.

This makes adding a new platform a much smaller operation, requiring fewer
changes that are scattered throughout the buildroot tree.

Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
diff --git a/openpower/configs/firenze_defconfig b/openpower/configs/firenze_defconfig
index 4c3c4ad..2b8ecc1 100644
--- a/openpower/configs/firenze_defconfig
+++ b/openpower/configs/firenze_defconfig
@@ -50,3 +50,4 @@
 # BR2_PACKAGE_CAPP_UCODE is not set
 BR2_PACKAGE_LOADKEYS=y
 # BR2_PACKAGE_IMA_CATALOG is not set
+# BR2_PACKAGE_MACHINE_XML is not set
\ No newline at end of file