powerpc: Add purgatory for kexec_file_load() implementation.

This purgatory implementation is based on the versions from kexec-tools
and kexec-lite, with additional changes.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 82ce8c8..31286fa 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -250,6 +250,7 @@
 core-$(CONFIG_XMON)		+= arch/powerpc/xmon/
 core-$(CONFIG_KVM) 		+= arch/powerpc/kvm/
 core-$(CONFIG_PERF_EVENTS)	+= arch/powerpc/perf/
+core-$(CONFIG_KEXEC_FILE)	+= arch/powerpc/purgatory/
 
 drivers-$(CONFIG_OPROFILE)	+= arch/powerpc/oprofile/