net: ti: icssg-prueth: Add AM64x icssg support

Add AM64x ICSSG support which is similar to am65x SR2.0, but required:
- all ring configured in exposed ring mode
- always fill both original and buffer fields in cppi5 desc

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>