target/loongarch: fix vldi/xvldi raise wrong error

target/loongarch: fix vldi/xvldi raise wrong error

on qemu we got an aborted error
**
ERROR:../target/loongarch/tcg/insn_trans/trans_vec.c.inc:3574:vldi_get_value: code should not be reached
Bail out! ERROR:../target/loongarch/tcg/insn_trans/trans_vec.c.inc:3574:vldi_get_value: code should not be reached
Aborted (core dumped)
but on 3A600/3A5000 we got a "Illegal instruction" error.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2971

Fixes: 29bb5d727ff ("target/loongarch: Implement vldi")
 Cc: qemu-stable@nongnu.org
Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Song Gao <gaosong@loongson.cn>