mlxsw: reg: Add bank number to MCIA register

Add bank number to MCIA (Management Cable Info Access) register in order
to allow access to banked pages on EEPROMs using CMIS (Common Management
Interface Specification) memory map.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>