Add Mellanox Technologies firmware flash module mlxfw to kernel.
https://github.com/Mellanox/mlxsw/wiki/Installing-a-New-Kernel#kernel-options
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