This adds support for the C5.6.147 RBIT instruction.
Signed-off-by: Alexander Graf <agraf@suse.de>
[claudio: adapted to new decoder, use bswap64,
make RBIT part standalone from the rest of the patch,
splitting REV into a separate patch] Signed-off-by: Claudio Fontana <claudio.fontana@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net>