target/arm: Rename TBFLAG_ANY, PSTATE_SS

target/arm: Rename TBFLAG_ANY, PSTATE_SS

We're about to rearrange the macro expansion surrounding tbflags,
and this field name will be expanded using the bit definition of
the same name, resulting in a token pasting error.

So PSTATE_SS -> PSTATE__SS in the uses, and document it.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210419202257.161730-4-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>