TX coalesced completions are supported on newer chips to provide
one TX completion record for multiple TX packets up to the
sq_cons_idx in the completion record.  This method saves PCIe
bandwidth by reducing the number of TX completions.

Only very minor changes are now required to support this mode
with the new framework that handles TX completions based on
the consumer indices.
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20231212005122.2401-6-michael.chan@broadcom.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>