HID: logitech-dj: add support for the static device in the Powerplay mat/receiver

The Logitech G Powerplay has a lightspeed receiver with a static HID++
device with ID 7 attached to it to. It is used to configure the led on
the mat. For this reason I increased the max number of devices.
Signed-off-by: NFilipe Laíns <lains@archlinux.org>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

drivers/hid/hid-logitech-dj.c

@@ -16,11 +16,11 @@
 #include <asm/unaligned.h>
 #include "hid-ids.h"
 
-#define DJ_MAX_PAIRED_DEVICES			6
+#define DJ_MAX_PAIRED_DEVICES			7
 #define DJ_MAX_NUMBER_NOTIFS			8
 #define DJ_RECEIVER_INDEX			0
 #define DJ_DEVICE_INDEX_MIN			1
-#define DJ_DEVICE_INDEX_MAX			6
+#define DJ_DEVICE_INDEX_MAX			7
 
 #define DJREPORT_SHORT_LENGTH			15
 #define DJREPORT_LONG_LENGTH			32
@@ -980,6 +980,11 @@ static void logi_hidpp_recv_queue_notif(struct hid_device *hdev,
 		break;
 	}
 
+	/* custom receiver device (eg. powerplay) */
+	if (hidpp_report->device_index == 7) {
+		workitem.reports_supported |= HIDPP;
+	}
+
 	if (workitem.type == WORKITEM_TYPE_EMPTY) {
 		hid_warn(hdev,
 			 "unusable device of type %s (0x%02x) connected on slot %d",