crypto: sha256 - Move lib/sha256.c to lib/crypto

Generic crypto implementations belong under lib/crypto not directly in
lib, likewise the header should be in include/crypto, not include/linux.

Note that the code in lib/crypto/sha256.c is not yet available for
generic use after this commit, it is still only used by the s390 and x86
purgatory code. Making it suitable for generic use is done in further
patches in this series.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/crypto/sha256.h

@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ *  Copyright (C) 2014 Red Hat Inc.
+ *
+ *  Author: Vivek Goyal <vgoyal@redhat.com>
+ */
+
+#ifndef SHA256_H
+#define SHA256_H
+
+#include <linux/types.h>
+#include <crypto/sha.h>
+
+/*
+ * Stand-alone implementation of the SHA256 algorithm. It is designed to
+ * have as little dependencies as possible so it can be used in the
+ * kexec_file purgatory. In other cases you should use the implementation in
+ * crypto/.
+ *
+ * For details see lib/crypto/sha256.c
+ */
+
+extern int sha256_init(struct sha256_state *sctx);
+extern int sha256_update(struct sha256_state *sctx, const u8 *input,
+			 unsigned int length);
+extern int sha256_final(struct sha256_state *sctx, u8 *hash);
+
+#endif /* SHA256_H */