Add witherspoon defconfig, p9 support for hostboot

Opened RTC issues 160270 and 160273 to fix patches that were
added.
diff --git a/openpower/configs/openpower_p9_mambo_defconfig b/openpower/configs/openpower_p9_mambo_defconfig
index 7dfbf8b..5a12266 100644
--- a/openpower/configs/openpower_p9_mambo_defconfig
+++ b/openpower/configs/openpower_p9_mambo_defconfig
@@ -35,10 +35,11 @@
 BR2_PACKAGE_RSYNC=y
 BR2_TARGET_ROOTFS_CPIO_XZ=y
 BR2_TARGET_ROOTFS_INITRAMFS=y
+BR2_OPENPOWER_POWER9=y
 BR2_OPENPOWER_PLATFORM=y
 # BR2_PACKAGE_HOSTBOOT is not set
 # BR2_PACKAGE_HOSTBOOT_BINARIES is not set
 # BR2_PACKAGE_OPENPOWER_PNOR is not set
 BR2_OPENPOWER_CONFIG_NAME="openpower-mambo-p9"
 BR2_PACKAGE_PETITBOOT=y
-# BR2_PACKAGE_OCC is not set
\ No newline at end of file
+# BR2_PACKAGE_OCC is not set