iwlwifi: pcie: clarify TX queue need_update handling

Similar to the recent RX queue patch, this changes the need_update
handling for the TX queues to be clearer and only done when needed.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

diff --cc drivers/net/wireless/iwlwifi/pcie/internal.h
Simple merge

diff --cc drivers/net/wireless/iwlwifi/pcie/rx.c
Simple merge

diff --cc drivers/net/wireless/iwlwifi/pcie/tx.c
Simple merge