During channge channel, tx power will not send to uCode, the tx power command
should send after scan complete. but should also can send after RXON command.

Stable fix identified by Stanislaw Gruszka <sgruszka@redhat.com>.
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Cc: stable@kernel.org [2.6.38+]
Signed-off-by: John W. Linville <linville@tuxdriver.com>