eth: bnxt: fix the wake condition

The down condition should be the negation of the wake condition,
IOW when I moved it from:

 if (cond && wake())
to
 if (__netif_txq_completed_wake(cond))

Cond should have been negated. Flip it now.

This bug leads to occasional crashes with netconsole.
It may also lead to queue never waking up in case BQL is not enabled.

Reported-by: David Wei <davidhwei@meta.com>
Fixes: 08a096780d92 ("bnxt: use new queue try_stop/try_wake macros")
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/20230607010826.960226-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>