rt2x00: change REGISTER_BUSY_COUNT for USB

Because of delays on USB we do not have to iterate so many times on
USB hardware when waiting for H/W register become valid.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
4 files changed