media: s5p-mfc: fix two sparse warnings

media-git/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c: In function 'vidioc_querycap':
media-git/drivers/media/platform/s5p-mfc/s5p_mfc_enc.c:1317:2: warning: 'strncpy' output may be truncated copying 31 bytes from a string of length 31 [-Wstringop-truncation]
  strncpy(cap->card, dev->vfd_enc->name, sizeof(cap->card) - 1);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
media-git/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c: In function 'vidioc_querycap':
media-git/drivers/media/platform/s5p-mfc/s5p_mfc_dec.c:275:2: warning: 'strncpy' output may be truncated copying 31 bytes from a string of length 31 [-Wstringop-truncation]
  strncpy(cap->card, dev->vfd_dec->name, sizeof(cap->card) - 1);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>