Eliminate sparse warning - bad constant expression

Eliminiate sparse warning during usage of crypto_shash_* APIs
       error: bad constant expression

Allocate memory for shash descriptors once, so that we do not kmalloc/kfree it
for every signature generation (shash descriptor for md5 hash).

From ed7538619817777decc44b5660b52268077b74f3 Mon Sep 17 00:00:00 2001
From: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Date: Tue, 24 Aug 2010 11:47:43 -0500
Subject: [PATCH] eliminate sparse warnings during crypto_shash_* APis usage
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

fs/cifs/cifsglob.h

@@ -123,12 +123,19 @@ struct cifs_cred {
 	struct cifs_ace *aces;
 };
 
+struct sdesc {
+	struct shash_desc shash;
+	char ctx[];
+};
+
 struct ntlmssp_auth {
 	__u32 client_flags;
 	__u32 server_flags;
 	unsigned char ciphertext[CIFS_CPHTXT_SIZE];
 	struct crypto_shash *hmacmd5;
 	struct crypto_shash *md5;
+	struct sdesc *sdeschmacmd5;
+	struct sdesc *sdescmd5;
 };
 
 /*