core: balloon: Add balloon_free() function

Signed-off-by: Chloe M. <chloe@mirocom.org>

mvm/core/balloon_subr.c

@@ -73,3 +73,16 @@ balloon_memcpy(struct mvm_balloon *dest, off_t off, void *source, size_t count)
     memcpy((char *)dest->data + off, source, count);
     return 0;
 }
+
+void
+balloon_free(struct mvm_balloon *bp)
+{
+    if (bp == NULL) {
+        return;
+    }
+
+    if (bp->data != NULL) {
+        free(bp->data);
+        bp->data = NULL;
+    }
+}