block/vmdk: Fix warning from splint (comparision of unsigned value)

l1_entry_sectors will never be less than 0.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
diff --git a/block/vmdk.c b/block/vmdk.c
index 5623ac1..45c003a 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -453,7 +453,7 @@
     }
     l1_entry_sectors = le32_to_cpu(header.num_gtes_per_gte)
                         * le64_to_cpu(header.granularity);
-    if (l1_entry_sectors <= 0) {
+    if (l1_entry_sectors == 0) {
         return -EINVAL;
     }
     l1_size = (le64_to_cpu(header.capacity) + l1_entry_sectors - 1)