net: driver: hamradio: Fix potential unterminated string

With W=1 the following error is reported:

In function ‘strncpy’,
    inlined from ‘hdlcdrv_ioctl’ at drivers/net/hamradio/hdlcdrv.c:600:4:
./include/linux/string.h:297:30: warning: ‘__builtin_strncpy’ specified bound 32 equals destination size [-Wstringop-truncation]
  297 | #define __underlying_strncpy __builtin_strncpy
      |                              ^
./include/linux/string.h:307:9: note: in expansion of macro ‘__underlying_strncpy’
  307 |  return __underlying_strncpy(p, q, size);

Replace strncpy with strlcpy to guarantee the string is terminated.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20201031181700.1081693-1-andrew@lunn.chSigned-off-by: NJakub Kicinski <kuba@kernel.org>

drivers/net/hamradio/hdlcdrv.c

@@ -597,7 +597,7 @@ static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 
 	case HDLCDRVCTL_DRIVERNAME:
 		if (s->ops && s->ops->drvname) {
-			strncpy(bi.data.drivername, s->ops->drvname, 
+			strlcpy(bi.data.drivername, s->ops->drvname,
 				sizeof(bi.data.drivername));
 			break;
 		}