media: dibx000_common: use strlcpy() instead of strncpy()

gcc-8 reports

drivers/media/dvb-frontends/dibx000_common.c: In function
'i2c_adapter_init':
./include/linux/string.h:245:9: warning: '__builtin_strncpy' specified
bound 48 equals destination size [-Wstringop-truncation]

We need to use strlcpy() to make sure the dest string is
nul-terminated.

Signed-off-by: Xiongfeng Wang <xiongfeng.wang@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>