Fix uninitialized value warnings.

Bug: 263274255
Test: presubmit; make tidy-build-make_subset
Change-Id: Ib6ce849596312f56e8d640c5f78e0e70f7ca54e3
diff --git a/tools/atree/fs.cpp b/tools/atree/fs.cpp
index 6cd080e..d004e97 100644
--- a/tools/atree/fs.cpp
+++ b/tools/atree/fs.cpp
@@ -177,7 +177,7 @@
         } else {
             // Split the arguments if more than 1
             char* cmd = strdup(strip_cmd);
-            const char** args = (const char**) malloc(sizeof(const char*) * (num_args + 2));
+            const char** args = (const char**) calloc((num_args + 2), sizeof(const char*));
 
             const char** curr = args;
             char* s = cmd;