net: airoha: Fix ETS priomap validation

net: airoha: Fix ETS priomap validation

ETS Qdisc schedules SP bands in a priority order assigning band-0 the
highest priority (band-0 > band-1 > .. > band-n) while EN7581 arranges
SP bands in a priority order assigning band-7 the highest priority
(band-7 > band-6, .. > band-n).
Fix priomap check in airoha_qdma_set_tx_ets_sched routine in order to
align ETS Qdisc and airoha_eth driver SP priority ordering.

Fixes: b56e4d660a96 ("net: airoha: Enforce ETS Qdisc priomap")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Davide Caratti <dcaratti@redhat.com>
Link: https://patch.msgid.link/20250331-airoha-ets-validate-priomap-v1-1-60a524488672@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>