powerpc/kexec: Enable kexec_file_load() syscall

Define the Kconfig symbol so that the kexec_file_load() code can be
built, and wire up the syscall so that it can be called.

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/Kconfig b/arch/powerpc/Kconfig
index a063c72..48923c3 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -465,6 +465,19 @@
 	  interface is strongly in flux, so no good recommendation can be
 	  made.
 
+config KEXEC_FILE
+	bool "kexec file based system call"
+	select KEXEC_CORE
+	select BUILD_BIN2C
+	depends on PPC64
+	depends on CRYPTO=y
+	depends on CRYPTO_SHA256=y
+	help
+	  This is a new version of the kexec system call. This call is
+	  file based and takes in file descriptors as system call arguments
+	  for kernel and initramfs as opposed to a list of segments as is the
+	  case for the older kexec call.
+
 config RELOCATABLE
 	bool "Build a relocatable kernel"
 	depends on (PPC64 && !COMPILE_TEST) || (FLATMEM && (44x || FSL_BOOKE))