lib: add crypt subsystem
Add the basic functionality required to support the standard crypt
format.
The files crypt-sha256.c and crypt-sha512.c originate from libxcrypt and
their formatting is therefor retained.
The integration is done via a crypt_compare() function in crypt.c.
```
libxcrypt $ git describe --long --always --all
tags/v4.4.17-0-g6b110bc
```
Signed-off-by: Steffen Jaeckel <jaeckel-floss@eyet-services.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
diff --git a/lib/crypt/Makefile b/lib/crypt/Makefile
new file mode 100644
index 0000000..d53b72b
--- /dev/null
+++ b/lib/crypt/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (c) 2021, Steffen Jaeckel <jaeckel-floss@eyet-services.de>
+
+obj-$(CONFIG_CRYPT_PW) += crypt.o
+obj-$(CONFIG_CRYPT_PW_SHA256) += crypt-sha256.o
+obj-$(CONFIG_CRYPT_PW_SHA512) += crypt-sha512.o