target/loongarch: Use actual operand size with vbsrl check

target/loongarch: Use actual operand size with vbsrl check

Hardcoded 32 bytes is used for vbsrl emulation check, there is
problem when options lsx=on,lasx=off is used for vbsrl.v instruction
in TCG mode. It injects LASX exception rather LSX exception.

Here actual operand size is used.

Cc: qemu-stable@nongnu.org
Fixes: df97f338076 ("target/loongarch: Implement xvreplve xvinsve0 xvpickve")
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>