net: ti: icssg-prueth: Add helper functions to configure FDB

commit 804f063eac872fccde489384cb2a54ecc915eb11 from
git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git

commit 487f7323f39a9d45a31c59e909de4a626f02d34f upstream

Introduce helper functions to configure firmware FDB tables, VLAN tables
and Port VLAN ID settings to aid adding Switch mode support.

Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Xulin Sun <xulin.sun@windriver.com>