Clean up a couple of consts and char pointers.

hmacmd5_do_hmac and hmac_sha1_simple should be consistently referring
to input memory blocks as 'const void *', but one had pointlessly
typed the pointer as 'const unsigned char *' and the other had missed
out the consts.

ssh.h

@@ -380,7 +380,7 @@ struct hmacmd5_context *hmacmd5_make_context(void);
 void hmacmd5_free_context(struct hmacmd5_context *ctx);
 void hmacmd5_key(struct hmacmd5_context *ctx, void const *key, int len);
 void hmacmd5_do_hmac(struct hmacmd5_context *ctx,
-                     unsigned char const *blk, int len, unsigned char *hmac);
+                     const void *blk, int len, unsigned char *hmac);
 
 int supports_sha_ni(void);
 
@@ -396,7 +396,8 @@ void SHA_Init(SHA_State * s);
 void SHA_Final(SHA_State * s, unsigned char *output);
 void SHA_Simple(const void *p, int len, unsigned char *output);
 
-void hmac_sha1_simple(void *key, int keylen, void *data, int datalen,
+void hmac_sha1_simple(const void *key, int keylen,
+                      const void *data, int datalen,
 		      unsigned char *output);
 typedef struct SHA256_State {
     uint32 h[8];

sshmd5.c

@@ -312,7 +312,7 @@ static void hmacmd5_genresult(ssh2_mac *mac, unsigned char *hmac)
 }
 
 void hmacmd5_do_hmac(struct hmacmd5_context *ctx,
-                     unsigned char const *blk, int len, unsigned char *hmac)
+                     const void *blk, int len, unsigned char *hmac)
 {
     ssh2_mac_start(&ctx->mac);
     put_data(&ctx->mac, blk, len);

sshsha.c

@@ -360,7 +360,8 @@ static void hmacsha1_genresult(ssh2_mac *mac, unsigned char *hmac)
     smemclr(intermediate, sizeof(intermediate));
 }
 
-void hmac_sha1_simple(void *key, int keylen, void *data, int datalen,
+void hmac_sha1_simple(const void *key, int keylen,
+                      const void *data, int datalen,
 		      unsigned char *output) {
     SHA_State states[2];
     unsigned char intermediate[20];