target/arm: Handle FPROUNDING_ODD in arm_rmode_to_sf

target/arm: Handle FPROUNDING_ODD in arm_rmode_to_sf

While this enumerator has been present since the first commit,
it isn't ever used.  The first actual use of round-to-odd came
with SVE, which currently uses float_round_to_odd instead of
the arm-specific enumerator.

Amusingly, the comment about unhandled TIEAWAY has been
out of date since the initial commit of translate-a64.c.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>