Kconfig: Add option for microcode filenames

Hardcoding the microcode filenames into the makefiles is great when
the microcode is in the blobs directory.  When the microcode isn't
posted to the blobs directory, we need some method of supplying the
microcode binary into the build.  This can of course be done manually
after the build has completed, as can be done with everything that
we're including in the ROM image.  Instead of making life hard for
everyone though, let's just add a way to specify where the microcode
rom comes from.

BUG=chrome-os-partner:53013

Change-Id: I7c5127234809e8515906efa56c04af6005eecf0b
Signed-off-by: Martin Roth <martinroth@chromium.org>
Reviewed-on: https://review.coreboot.org/16386
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Omar Pakker
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/cpu/Kconfig

@@ -166,3 +166,18 @@ config CPU_MICROCODE_HEADER_FILES
 	help
 	  A list of one or more microcode header files with path from the
 	  coreboot directory.  These should be separated by spaces.
+
+config CPU_UCODE_BINARIES
+	string "Microcode binary path and filename"
+	depends on CPU_MICROCODE_CBFS_GENERATE
+	default ""
+	help
+	  Some platforms have microcode in the blobs directory, and these can
+	  be hardcoded in the makefiles.  For platforms with microcode
+	  binaries that aren't in the makefile, set this option to pull
+	  in the microcode.
+
+	  This should contain the full path of the file for one or more
+	  microcode binary files to include, separated by spaces.
+
+	  If unsure, leave this blank.

src/cpu/intel/microcode/Makefile.inc

@@ -4,3 +4,5 @@
 ################################################################################
 ramstage-$(CONFIG_SUPPORT_CPU_UCODE_IN_CBFS) += microcode.c
 romstage-$(CONFIG_SUPPORT_CPU_UCODE_IN_CBFS) += microcode.c
+
+cpu_microcode_bins += $(call strip_quotes,$(CONFIG_CPU_UCODE_BINARIES))