display: Remove klockwork warnings and errors.

Remove all klockwork warnings and errors for libgralloc,
libhwcomposer, liboverlay, libqdutils, libqservice, libvirtual,
libexternal libraries to avoid buffer overflow and memory leaks.

Change-Id: I078143bcbcf5e4b342156bd8305a644566f7cc4b
diff --git a/libvirtual/virtual.cpp b/libvirtual/virtual.cpp
index 342044c..795d8a1 100644
--- a/libvirtual/virtual.cpp
+++ b/libvirtual/virtual.cpp
@@ -191,7 +191,7 @@
                                    getFbForDpy(HWC_DISPLAY_VIRTUAL);
 
         char strDevPath[MAX_SYSFS_FILE_PATH];
-        sprintf(strDevPath,"/dev/graphics/fb%d", fbNum);
+        snprintf(strDevPath,sizeof(strDevPath), "/dev/graphics/fb%d", fbNum);
 
         mFd = open(strDevPath, O_RDWR);
         if(mFd < 0) {