target/loongarch: Fix vldi inst

target/loongarch: Fix vldi inst

Refer to the link below for a description of the vldi instructions:
https://jia.je/unofficial-loongarch-intrinsics-guide/lsx/misc/#synopsis_88
Fixed errors in vldi instruction implementation.

Signed-off-by: Guo Hongyu <guohongyu24@mails.ucas.ac.cn>
Tested-by: Xianglai Li <lixianglai@loongson.cn>
Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
(cherry picked from commit 02ce6cea71be4f6774351f5e658d50044c5b53b2)
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2865
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>