payloads/external/Memtest86Plus: allow for selecting a specific revision

Because the Kconfig configuration files for primary payloads are
already sourced via a wildcard pattern this change requires to
use another file name pattern.

Change-Id: I83b89f5e14618e8a487ebb044fcdd3c175662591
Signed-off-by: Stefan Tauner <stefan.tauner@gmx.at>
Reviewed-on: https://review.coreboot.org/28217
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>

payloads/external/Memtest86Plus/Kconfig.secondary

@@ -0,0 +1,42 @@
+if MEMTEST_SECONDARY_PAYLOAD
+
+choice
+	prompt "Memtest86+ version"
+	default MEMTEST_STABLE
+	depends on MEMTEST_SECONDARY_PAYLOAD
+
+config MEMTEST_STABLE
+	bool "Stable"
+	help
+	  Stable Memtest86+ version.
+
+	  For reproducible builds, this option must be selected.
+config MEMTEST_MASTER
+	bool "Master"
+	help
+	  Newest Memtest86+ version.
+
+	  This option will fetch the newest version of the Memtest86+ code,
+	  updating as new changes are committed.  This makes the build
+	  non-reproducible, as it can fetch different code each time.
+config MEMTEST_REVISION
+	bool "git revision"
+	help
+	  Select this option if you have a specific commit or branch
+	  that you want to use as the revision from which to
+	  build Memtest86+.  This makes the build
+	  non-reproducible, as it can fetch different code each time.
+
+	  You will be able to specify the name of a branch or a commit id
+	  later.
+
+endchoice
+
+config MEMTEST_REVISION_ID
+	string "Insert a commit's SHA-1 or a branch name"
+	depends on MEMTEST_REVISION
+	default "origin/master"
+	help
+	   The commit's SHA-1 or branch name of the revision to use.
+
+endif