media: renesas-ceu: keep input name simple

Just show the Camera index as input name in VIDIOC_ENUM_INPUT,
no need to show the subdev name as well as that is meaningless for
users anyway.

This fixes this compiler warning:

drivers/media/platform/renesas/renesas-ceu.c: In function 'ceu_enum_input':
drivers/media/platform/renesas/renesas-ceu.c:1195:59: warning: '%s' directive output may be truncated writing up to 47 bytes into a region of size between 14 and 23 [-Wformat-truncation=]
 1195 |         snprintf(inp->name, sizeof(inp->name), "Camera%u: %s",
      |                                                           ^~
drivers/media/platform/renesas/renesas-ceu.c:1195:9: note: 'snprintf' output between 10 and 66 bytes into a destination of size 32
 1195 |         snprintf(inp->name, sizeof(inp->name), "Camera%u: %s",
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 1196 |                  inp->index, ceusd->v4l2_sd->name);
      |                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>