LoongArch: Fix module relocation error with binutils 2.41

Binutils 2.41 enables linker relaxation by default, but the kernel
module loader doesn't support that, so just disable it. Otherwise we
get such an error when loading modules:

"Unknown relocation type 102"

As an alternative, we could add linker relaxation support in the kernel
module loader. But it is relatively large complexity that may or may not
bring a similar gain, and we don't really want to include this linker
pass in the kernel.

Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>