firmware: turris-mox-rwtm: report failures better

Report a notice level message if a command is not supported by the rWTM
firmware.

This should not be an error, merely a notice, because the firmware can
be used on boards that do not have manufacturing information burned.

Fixes: 389711b374 ("firmware: Add Turris Mox rWTM firmware driver")
Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>

drivers/firmware/turris-mox-rwtm.c

@@ -204,11 +204,14 @@ static int mox_get_board_info(struct mox_rwtm *rwtm)
 		return ret;
 
 	ret = mox_get_status(MBOX_CMD_BOARD_INFO, reply->retval);
-	if (ret < 0 && ret != -ENODATA) {
-		return ret;
-	} else if (ret == -ENODATA) {
+	if (ret == -ENODATA) {
 		dev_warn(rwtm->dev,
 			 "Board does not have manufacturing information burned!\n");
+	} else if (ret == -ENOSYS) {
+		dev_notice(rwtm->dev,
+			   "Firmware does not support the BOARD_INFO command\n");
+	} else if (ret < 0) {
+		return ret;
 	} else {
 		rwtm->serial_number = reply->status[1];
 		rwtm->serial_number <<= 32;
@@ -237,10 +240,13 @@ static int mox_get_board_info(struct mox_rwtm *rwtm)
 		return ret;
 
 	ret = mox_get_status(MBOX_CMD_ECDSA_PUB_KEY, reply->retval);
-	if (ret < 0 && ret != -ENODATA) {
-		return ret;
-	} else if (ret == -ENODATA) {
+	if (ret == -ENODATA) {
 		dev_warn(rwtm->dev, "Board has no public key burned!\n");
+	} else if (ret == -ENOSYS) {
+		dev_notice(rwtm->dev,
+			   "Firmware does not support the ECDSA_PUB_KEY command\n");
+	} else if (ret < 0) {
+		return ret;
 	} else {
 		u32 *s = reply->status;