staging: wfx: simplify hif_set_pm() usage

The struct hif_req_set_pm_mode comes from hardware API. It is not
intended to be manipulated in upper layers of the driver. So, this patch
relocate the handling of this struct to hif_set_pm() (the low level
function).

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20191217161318.31402-41-Jerome.Pouiller@silabs.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>