[IA64] hpsim: Fix check for overlong simscsi prefix.

When "strlen(s) > MAX_ROOT_LEN", it has already said to use the default
value, but in fact, it still use the input value.

If happens, next sprintf() for 'fname' in simscsi_queuecommand_lck()
may be memory overflow.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/hp/sim/simscsi.c

@@ -88,8 +88,8 @@ simscsi_setup (char *s)
 	if (strlen(s) > MAX_ROOT_LEN) {
 		printk(KERN_ERR "simscsi_setup: prefix too long---using default %s\n",
 		       simscsi_root);
-	}
-	simscsi_root = s;
+	} else
+		simscsi_root = s;
 	return 1;
 }