modules: camera: fix compiler warnings

Change-Id: Id1aa624d377776a7e37b52978664d30c927595be
diff --git a/modules/camera/CameraHAL.cpp b/modules/camera/CameraHAL.cpp
index 0d8164c..dfbbe4c 100644
--- a/modules/camera/CameraHAL.cpp
+++ b/modules/camera/CameraHAL.cpp
@@ -92,6 +92,10 @@
     char *nameEnd;
 
     ALOGV("%s: module=%p, name=%s, device=%p", __func__, mod, name, dev);
+    if (*name == '\0') {
+        ALOGE("%s: Invalid camera id name is NULL", __func__);
+        return -EINVAL;
+    }
     id = strtol(name, &nameEnd, 10);
     if (*nameEnd != '\0') {
         ALOGE("%s: Invalid camera id name %s", __func__, name);