Add Mellanox Technologies firmware flash module `mlxfw` to kernel.
Expected kernel modules:
```
CONFIG_MLXFW=m
CONFIG_MLXSW_CORE=m
CONFIG_MLXSW_CORE_HWMON=m
CONFIG_MLXSW_CORE_THERMAL=m
CONFIG_MLXSW_PCI=m
CONFIG_MLXSW_I2C=m
CONFIG_MLXSW_MINIMAL=m
CONFIG_MLXSW_SWITCHX2=m
CONFIG_MLXSW_SPECTRUM=m
CONFIG_MLXSW_SPECTRUM_DCB=m
```