crypto: ghash-generic - move common definitions to a new header file

Move common values and types used by ghash-generic to a new header file
so drivers can directly use ghash-generic as a fallback implementation.

Fixes: cc333cd68dfa ("crypto: vmx - Adding GHASH routines for VMX module")
Cc: stable@vger.kernel.org
Signed-off-by: Marcelo Cerri <marcelo.cerri@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/include/crypto/ghash.h b/include/crypto/ghash.h
new file mode 100644
index 0000000..2a61c9b
--- /dev/null
+++ b/include/crypto/ghash.h
@@ -0,0 +1,23 @@
+/*
+ * Common values for GHASH algorithms
+ */
+
+#ifndef __CRYPTO_GHASH_H__
+#define __CRYPTO_GHASH_H__
+
+#include <linux/types.h>
+#include <crypto/gf128mul.h>
+
+#define GHASH_BLOCK_SIZE	16
+#define GHASH_DIGEST_SIZE	16
+
+struct ghash_ctx {
+	struct gf128mul_4k *gf128;
+};
+
+struct ghash_desc_ctx {
+	u8 buffer[GHASH_BLOCK_SIZE];
+	u32 bytes;
+};
+
+#endif