eth: bnxt: fix string truncation warning in FW version

W=1 builds with gcc 14.2.1 report:

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c:4193:32: error: ‘%s’ directive output may be truncated writing up to 31 bytes into a region of size 27 [-Werror=format-truncation=]
 4193 |                          "/pkg %s", buf);

It's upset that we let buf be full length but then we use 5
characters for "/pkg ".

The builds is also clear with clang version 19.1.5 now.

Reviewed-by: Michael Chan <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

@@ -4184,7 +4184,7 @@ int bnxt_get_pkginfo(struct net_device *dev, char *ver, int size)
 static void bnxt_get_pkgver(struct net_device *dev)
 {
 	struct bnxt *bp = netdev_priv(dev);
-	char buf[FW_VER_STR_LEN];
+	char buf[FW_VER_STR_LEN - 5];
 	int len;
 
 	if (!bnxt_get_pkginfo(dev, buf, sizeof(buf))) {