media: verisilicon: replace snprintf with strscpy+strlcat

Fixes this warning:

drivers/media/platform/verisilicon/hantro_drv.c: In function 'hantro_add_func':
drivers/media/platform/verisilicon/hantro_drv.c:902:49: warning: '%s' directive output may be truncated writing up to 127 bytes into a region of size 64 [-Wformat-truncation=]
  902 |         snprintf(vfd->name, sizeof(vfd->name), "%s-%s", match->compatible,
      |                                                 ^~
drivers/media/platform/verisilicon/hantro_drv.c:902:9: note: 'snprintf' output between 5 and 132 bytes into a destination of size 64
  902 |         snprintf(vfd->name, sizeof(vfd->name), "%s-%s", match->compatible,
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  903 |                  funcid == MEDIA_ENT_F_PROC_VIDEO_ENCODER ? "enc" : "dec");
      |                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/media/platform/verisilicon/hantro_drv.c:902:49: warning: '%s' directive output may be truncated writing up to 127 bytes into a region of size 64 [-Wformat-truncation=]
  902 |         snprintf(vfd->name, sizeof(vfd->name), "%s-%s", match->compatible,
      |                                                 ^~
drivers/media/platform/verisilicon/hantro_drv.c:902:9: note: 'snprintf' output between 5 and 132 bytes into a destination of size 64
  902 |         snprintf(vfd->name, sizeof(vfd->name), "%s-%s", match->compatible,
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  903 |                  funcid == MEDIA_ENT_F_PROC_VIDEO_ENCODER ? "enc" : "dec");
      |                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>