Add support for lm32 CFG2 and MMU related CSR registers in binutils
Add support for .stringz instruction in gcc for lm32
Fix function declaration for lm32 arch in gcc
Add support for a few built-ins in gcc lm32 arch
Improve performances using hardware blocks instead of software defined builtins for multiplications, divisions, shift and sign extension
Add TODO
Add support for lm32 built-ins in libkern

This is necessary because kernel is not linked against libgcc.
Add support for lm32 CPU and Milkymist SoC in NetBSD kernel (WIP)