sandbox: Use uint64_t instead of u64 for time

The uint64_t type is defined in linux/types.h, so is safer than u64, which
is not actually a Linux type.

Change-Id: Ifc9a369e6543250c49117b8d3cb3a676eee43e04
Signed-off-by: Simon Glass <sjg@chromium.org>
2 files changed