docs/zh_CN/LoongArch: Add I14 description

I14 is also a kind of immediate operand in instruction, like I8/I12/I16/
I21/I26, add it in the Chinese documentation.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
1 file changed