Not all LoongArch cores support h/w unaligned access, we can use
-mstrict-align build parameter to prevent unaligned accesses.

CPUs with h/w unaligned access support:
Loongson-2K2000/2K3000/3A5000/3C5000/3D5000.

CPUs without h/w unaligned access support:
Loongson-2K500/2K1000.

This option is enabled by default to make the kernel be able to run
on all LoongArch systems. But you can disable it manually if you want
to run kernel only on systems with h/w unaligned access support in
order to optimise for performance.