tcg/mips: mips sync* encode error

tcg/mips: mips sync* encode error

OPC_SYNC_WMB, OPC_SYNC_MB, OPC_SYNC_ACQUIRE, OPC_SYNC_RELEASE and
OPC_SYNC_RMB have wrong encode. According to the mips manual,
their encode should be 'OPC_SYNC | 0x?? << 6' rather than
'OPC_SYNC | 0x?? << 5'. Wrong encode can lead illegal instruction
errors. These instructions often appear with multi-threaded
simulation.

Fixes: 6f0b99104a3 ("tcg/mips: Add support for fence")
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: lixinyu <precinct@mail.ustc.edu.cn>
Message-Id: <20200411124612.12560-1-precinct@mail.ustc.edu.cn>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>