[PATCH] bcm43xx: fix radio_set_tx_iq

Fix a duplicated leftshift in bcm43xx_radio_set_tx_iq. data_high values are
already leftshifted. Thanks to Michael Buesch for spotting this.

Signed-off-by: Stefano Brivio <stefano.brivio@polimi.it>
Signed-off-by: John W. Linville <linville@tuxdriver.com>