p54: implement set_coverage_class

The callback sets slot time as specified in IEEE 802.11-2007
section 17.3.8.6 and raises round trip delay accordingly.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/p54/p54.h

@@ -217,6 +217,7 @@ struct p54_common {
 	u32 tsf_low32, tsf_high32;
 	u32 basic_rate_mask;
 	u16 aid;
+	u8 coverage_class;
 	bool powersave_override;
 	__le32 beacon_req_id;
 	struct completion beacon_comp;