net: ethernet: am65-cpsw: Rename TI_AM65_CPSW_TAS to TI_AM65_CPSW_QOS

We will use this Kconfig option to not only enable TAS/EST offload
but also other QoS features like Multiqueue priority descriptors
and MAC-Merge/Frame Preemption. TI_AM65_CPSW_QOS seems a more
appropriate Kconfig option name than TI_AM65_CPSW_TAS.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>