bnxt_en: add support for hds-thresh ethtool command

The bnxt_en driver has configured the hds_threshold value automatically
when TPA is enabled based on the rx-copybreak default value.
Now the hds-thresh ethtool command is added, so it adds an
implementation of hds-thresh option.

Configuration of the hds-thresh is applied only when
the tcp-data-split is enabled. The default value of
hds-thresh is 256, which is the default value of
rx-copybreak, which used to be the hds_thresh value.

The maximum hds-thresh is 1023.

   # Example:
   # ethtool -G enp14s0f0np0 tcp-data-split on hds-thresh 256
   # ethtool -g enp14s0f0np0
   Ring parameters for enp14s0f0np0:
   Pre-set maximums:
   ...
   HDS thresh:  1023
   Current hardware settings:
   ...
   TCP data split:         on
   HDS thresh:  256

Tested-by: Stanislav Fomichev <sdf@fomichev.me>
Tested-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20250114142852.3364986-9-ap420073@gmail.com


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