ath9k_hw: remove pCap->total_queues

The EEPROM contains a field that can restrict the number of hardware queues,
however this is not only useless (all the known chips contain the same
number of hardware queues), but also potentially dangerous in case of a
misprogrammed EEPROM (could trigger driver crashes), so let's just ignore
it completely.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>