Expose device firmware version via devlink info_get().

Example output:
  $ devlink dev
  pci/0000:07:00.0
  pci/0000:08:00.0
  pci/0000:09:00.0

  $ devlink dev info
  pci/0000:07:00.0:
    driver kvaser_pciefd
    versions:
        running:
          fw 1.3.75
  pci/0000:08:00.0:
    driver kvaser_pciefd
    versions:
        running:
          fw 2.4.29
  pci/0000:09:00.0:
    driver kvaser_pciefd
    versions:
        running:
          fw 1.3.72

Signed-off-by: Jimmy Assarsson <redacted>
---
Changes in v2:
  - Add two space indentation to terminal output. Suggested by Vincent Mailhol [1]
  - Replaced fixed-size char array with a string literal to let the compiler determine the buffer size automatically. Suggested by Vincent Mailhol [2]

[1] https://lore.kernel.org/linux-can/20250723083236.9-1-extja@kvaser.com/T/#m31ee4aad13ee29d5559b56fdce842609ae4f67c5 (local)
[2] https://lore.kernel.org/linux-can/20250723083236.9-1-extja@kvaser.com/T/#m97df78a8b0bafa6fe888f5fc0c27d0a05877bdaf (local)

 .../can/kvaser_pciefd/kvaser_pciefd_devlink.c | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/net/can/kvaser_pciefd/kvaser_pciefd_devlink.c b/drivers/net/can/kvaser_pciefd/kvaser_pciefd_devlink.c
index 8145d25943de..4e4550115368 100644
--- a/drivers/net/can/kvaser_pciefd/kvaser_pciefd_devlink.c
+++ b/drivers/net/can/kvaser_pciefd/kvaser_pciefd_devlink.c

@@ -4,7 +4,33 @@
  * Copyright (C) 2025 KVASER AB, Sweden. All rights reserved.
  */
 
+#include "kvaser_pciefd.h"
+
 #include <net/devlink.h>
 
+static int kvaser_pciefd_devlink_info_get(struct devlink *devlink,
+					  struct devlink_info_req *req,
+					  struct netlink_ext_ack *extack)
+{
+	struct kvaser_pciefd *pcie = devlink_priv(devlink);
+	char buf[] = "xxx.xxx.xxxxx";
+	int ret;
+
+	if (pcie->fw_version.major) {
+		snprintf(buf, sizeof(buf), "%u.%u.%u",
+			 pcie->fw_version.major,
+			 pcie->fw_version.minor,
+			 pcie->fw_version.build);
+		ret = devlink_info_version_running_put(req,
+						       DEVLINK_INFO_VERSION_GENERIC_FW,
+						       buf);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 const struct devlink_ops kvaser_pciefd_devlink_ops = {
+	.info_get = kvaser_pciefd_devlink_info_get,
 };

-- 
2.49.0