Octeontx2-pf: ethtool: support multi advertise mode

Current implementation considers only first advertise
mode and passes the same to firmware to process.
This patch extends code such that user can advertise
multiple modes on the given interface.

Below are high level changes:

1. Remove unnecessary speed/duplex/autoneg validation as its
   already verified as part of "set_link_ksettings"

2. Since scratch csr framework designed to support single mode at a time,
   use "shared firmware data" for multi mode support.

Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Link: https://patch.msgid.link/20250625092107.9746-4-hkelam@marvell.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>