bnxt_en: avoid newline at end of message in NL_SET_ERR_MSG_MOD

Fix following coccicheck warning:
./drivers/net/ethernet/broadcom/bnxt/bnxt_devlink.c:446:8-56: WARNING
avoid newline at end of message in NL_SET_ERR_MSG_MOD.
Signed-off-by: NWan Jiabing <wanjiabing@vivo.com>
Link: https://lore.kernel.org/r/20211102020312.16567-1-wanjiabing@vivo.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

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

@@ -443,7 +443,7 @@ static int bnxt_dl_reload_down(struct devlink *dl, bool netns_change,
 	case DEVLINK_RELOAD_ACTION_DRIVER_REINIT: {
 		if (BNXT_PF(bp) && bp->pf.active_vfs) {
 			NL_SET_ERR_MSG_MOD(extack,
-					   "reload is unsupported when VFs are allocated\n");
+					   "reload is unsupported when VFs are allocated");
 			return -EOPNOTSUPP;
 		}
 		rtnl_lock();