target/arm: Add wrapper macros for accessing tbflags

We're about to split tbflags into two parts.  These macros
will ensure that the correct part is used with the correct
set of bits.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210419202257.161730-5-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
5 files changed