[Bug target/106097] undefined behaviors regarding integer shifts in loongarch_build_integer

[chenglulu at loongson dot cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106097

--- Comment #8 from chenglulu <chenglulu at loongson dot cn> ---
> You can reuse LU32I_B and LU52I_B instead of hard coding those long
> constants :).

I have fixed it, thanks！:)