iwlwifi: fix frame injection for HT channels

For some reason, sending QoS configuration causes transmission to stop
after a single frame on HT channels when not associated. Removing the
extra QoS configuration has no effect on station mode, and fixes
injection mode.

Signed-off-by: Daniel Halperin <dhalperi@cs.washington.edu>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>