We are inconsistent with the type of tb->flags: usage varies loosely
between int and uint64_t. Settle to uint32_t everywhere, which is
superior to both: at least one target (aarch64) uses the most significant
bit in the u32, and uint64_t is wasteful.

Compile-tested for all targets.
Suggested-by: NLaurent Desnogues <laurent.desnogues@gmail.com>
Suggested-by: NRichard Henderson <rth@twiddle.net>
Tested-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: NEdgar E. Iglesias <edgar.iglesias@xilinx.com>
Reviewed-by: NLaurent Desnogues <laurent.desnogues@gmail.com>
Signed-off-by: NEmilio G. Cota <cota@braap.org>
Signed-off-by: NRichard Henderson <rth@twiddle.net>
Message-Id: <1460049562-23517-1-git-send-email-cota@braap.org>