Miihawk update xml and p9Layout

Update mihawk-xml version in mihawk_defconfig

Update openpower-pnor patch file to increase Bootloader Kernel
partition size to 24MB for built-in tools support.

Signed-off-by: Nichole Wang <Nichole_Wang@wistron.com>
Signed-off-by: Klaus Heinrich Kiwi <klaus@linux.vnet.ibm.com>
                      (squashed and commit message)
diff --git a/openpower/configs/mihawk_defconfig b/openpower/configs/mihawk_defconfig
index b0b350a..b405a13 100644
--- a/openpower/configs/mihawk_defconfig
+++ b/openpower/configs/mihawk_defconfig
@@ -50,7 +50,7 @@
 BR2_OPENPOWER_POWER9=y
 BR2_HOSTBOOT_CONFIG_FILE="mihawk.config"
 BR2_OPENPOWER_MACHINE_XML_GITHUB_PROJECT_VALUE="mihawk-xml"
-BR2_OPENPOWER_MACHINE_XML_VERSION="f6ec5aa0f9803d44b147a7670dec7ec935f59582"
+BR2_OPENPOWER_MACHINE_XML_VERSION="8efcc795ddaad85a242d7b1e1d3654f1c79f7c4e"
 BR2_OPENPOWER_MACHINE_XML_FILENAME="mihawk.xml"
 BR2_OPENPOWER_SYSTEM_XML_FILENAME="MIHAWK_hb.system.xml"
 BR2_OPENPOWER_MRW_XML_FILENAME="MIHAWK_hb.mrw.xml"