qdutils: Fix memory leak

In one of the one-time operations, memory was allocated for reading
lines from a sysfs node, but not freed subsequently. This patch
addresses that.

Change-Id: I31dfd922a0aa02a9a4ef02b0d3a0f049c0cac08a
diff --git a/libqdutils/mdp_version.cpp b/libqdutils/mdp_version.cpp
index e045918..a6a1b85 100644
--- a/libqdutils/mdp_version.cpp
+++ b/libqdutils/mdp_version.cpp
@@ -256,6 +256,7 @@
                 ALOGI("PartialUpdate disabled by property");
         }
         fclose(panelInfoNodeFP);
+        free(readLine);
     } else {
         ALOGE("Failed to open msm_fb_panel_info node");
     }