staging: wfx: simplify hif_set_output_power() usage

staging: wfx: simplify hif_set_output_power() usage

Hardware API use 10th of dBm for output power unit. Upper layers should
use same units than mac80211 and the conversion should be done by low
level layer of the driver (hif_set_output_power())

In add, current code of hif_set_output_power() use a __le32 while the
device API specify a specific structure for this.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200115135338.14374-7-Jerome.Pouiller@silabs.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>