mt76: mt7921: fix a precision vs width bug in printk

Precision %.*s was intended instead of width %*s. The original code
is potentially an information leak.

Fixes: c7cc5ec57303 ("mt76: mt7921: rework mt7921_mcu_debug_msg_event routine")
Signed-off-by: Dan Carpenter <[e-mail]>
Signed-off-by: Felix Fietkau <[e-mail]>

drivers/net/wireless/mediatek/mt76/mt7921/mcu.c

···
 			if (!msg->content[i])
 				msg->content[i] = ' ';
 		}
-		wiphy_info(mt76_hw(dev)->wiphy, "%*s", len, msg->content);
+		wiphy_info(mt76_hw(dev)->wiphy, "%.*s", len, msg->content);
 	}
 }