target/tricore: Correctly handle FPU RM from PSW

target/tricore: Correctly handle FPU RM from PSW

when we reconstructed PSW using psw_read(), we were trying to clear the
cached USB bits out of env->PSW. The mask was wrong and we would clear
PSW.RM as well.

when we write the PSW using psw_write() we update the rounding modes in
env->fp_status for softfloat. The order of bits used by TriCore is not
the one used by softfloat.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Message-ID: <20230828112651.522058-4-kbastian@mail.uni-paderborn.de>