[PATCH] _SPrint: fix NULL termination

maxlen is the maximum string length not the buffer size.

Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Signed-off-by: Nigel Croxon <nigel.croxon@hp.com>

lib/print.c

@@ -345,7 +345,7 @@ _SPrint (
     if (spc->len < spc->maxlen) {
         spc->str[spc->len] = 0;
     } else if (spc->maxlen) {
-        spc->str[spc->maxlen-1] = 0;
+        spc->str[spc->maxlen] = 0;
     }
 
     return 0;