rt2x00: Fix transfer speed regression for USB hardware

Patch:
  rt2x00: Make rt2x00_queue_entry_for_each more flexible
  commit: 10e11568

introduced a severe regression on the throughput
for USB hardware. It turns out that the exiting of
the rt2x00queue_for_each_entry() was done too early.

The exact cause for this regression is unknown,
but by disabling the premature exiting of the loop
seems to resolve the issue.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Reported-by: Yasushi SHOJI <yashi@atmark-techno.com>
Reported-by: Balint Viragh <bviragh@dension.com>
Tested-by: Balint Viragh <bviragh@dension.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>