Check the payload length if checksumming to ensure the payload contains
the space for the resulting value.
This bug was found by Alexander Bulekov with the fuzzer:
https://patchew.org/QEMU/20230129053316.1071513-1-alxndr@bu.edu/
The fixed test case is:
fuzz/crash_6aeaa33e7211ecd603726c53e834df4c6d1e08bc
Fixes: e263cd49c7 ("Packet abstraction for VMWARE network devices")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>