HID: logitech-hidpp: Do not flood kernel log

Since commit 680ee411a98e ("HID: logitech-hidpp: Fix connect event race")
the following messages appear in the kernel log from time to time:

logitech-hidpp-device 0003:046D:408A.0005: HID++ 4.5 device connected.
logitech-hidpp-device 0003:046D:408A.0005: HID++ 4.5 device connected.
logitech-hidpp-device 0003:046D:4051.0006: Disconnected
logitech-hidpp-device 0003:046D:408A.0005: Disconnected

As discussed, print the first per-device "device connected" message
at info level, demoting subsequent messages to debug level. Also,
demote the "Disconnected message" to debug level unconditionally.

Link: https://lore.kernel.org/lkml/[e-mail]/
Signed-off-by: Oleksandr Natalenko <[e-mail]>
Reviewed-by: Hans de Goede <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>

drivers/hid/hid-logitech-hidpp.c

···
 	struct hidpp_scroll_counter vertical_wheel_counter;
 
 	u8 wireless_feature_index;
+
+	bool connected_once;
 };
 
 /* HID++ 1.0 error codes */
···
 	hidpp->protocol_minor = response.rap.params[1];
 
 print_version:
-	hid_info(hidpp->hid_dev, "HID++ %u.%u device connected.\n",
-		 hidpp->protocol_major, hidpp->protocol_minor);
+	if (!hidpp->connected_once) {
+		hid_info(hidpp->hid_dev, "HID++ %u.%u device connected.\n",
+			 hidpp->protocol_major, hidpp->protocol_minor);
+		hidpp->connected_once = true;
+	} else
+		hid_dbg(hidpp->hid_dev, "HID++ %u.%u device connected.\n",
+			 hidpp->protocol_major, hidpp->protocol_minor);
 	return 0;
 }
 
···
 	/* Get device version to check if it is connected */
 	ret = hidpp_root_get_protocol_version(hidpp);
 	if (ret) {
-		hid_info(hidpp->hid_dev, "Disconnected\n");
+		hid_dbg(hidpp->hid_dev, "Disconnected\n");
 		if (hidpp->battery.ps) {
 			hidpp->battery.online = false;
 			hidpp->battery.status = POWER_SUPPLY_STATUS_UNKNOWN;