Merge branch 'mlnx-i2c'

Ohad Oz says:

====================
Enable Mellanox switch device in I2C mode

The following patch set updates global to Mellanox Kconfig files to support
configuration of Mellanox Switch (mlxsw) without PCI and with I2C only.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>