Fixes this compiler warning:

drivers/media/pci/cx18/cx18-driver.c: In function 'cx18_init_struct1':
drivers/media/pci/cx18/cx18-driver.c:688:65: warning: '%s' directive output may be truncated writing up to 35 bytes into a region of size 11 [-Wformat-truncation=]
  688 |         snprintf(cx->in_workq_name, sizeof(cx->in_workq_name), "%s-in",
      |                                                                 ^~
In function 'cx18_create_in_workq',
    inlined from 'cx18_init_struct1' at drivers/media/pci/cx18/cx18-driver.c:724:8:
drivers/media/pci/cx18/cx18-driver.c:688:9: note: 'snprintf' output between 4 and 39 bytes into a destination of size 11
  688 |         snprintf(cx->in_workq_name, sizeof(cx->in_workq_name), "%s-in",
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  689 |                  cx->v4l2_dev.name);
      |                  ~~~~~~~~~~~~~~~~~~
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Arnd Bergmann <arnd@arndb.de>