liboverlay: remove warnings during compilation

- Remove unused variables
- Use proper typecast

Change-Id: Ia60fc4c3c7ec39a1df4a780de7f5d75d723f7960
diff --git a/liboverlay/overlayUtils.cpp b/liboverlay/overlayUtils.cpp
index 30de1db..5cc4c03 100644
--- a/liboverlay/overlayUtils.cpp
+++ b/liboverlay/overlayUtils.cpp
@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
+* Copyright (c) 2011-2014, The Linux Foundation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
@@ -423,7 +423,7 @@
     getDump(buf, len, "\tdst_rect", ov.dst_rect);
 }
 
-void getDump(char *buf, size_t len, const char *prefix,
+void getDump(char *buf, size_t /*len*/, const char *prefix,
         const msmfb_img& ov) {
     char str_src[256] = {'\0'};
     snprintf(str_src, 256,
@@ -433,7 +433,7 @@
     strncat(buf, str_src, strlen(str_src));
 }
 
-void getDump(char *buf, size_t len, const char *prefix,
+void getDump(char *buf, size_t /*len*/, const char *prefix,
         const mdp_rect& ov) {
     char str_rect[256] = {'\0'};
     snprintf(str_rect, 256,
@@ -452,7 +452,7 @@
     getDump(buf, len, "\tdata", ov.data);
 }
 
-void getDump(char *buf, size_t len, const char *prefix,
+void getDump(char *buf, size_t /*len*/, const char *prefix,
         const msmfb_data& ov) {
     char str_data[256] = {'\0'};
     snprintf(str_data, 256,