media: radio-shark2: Avoid led_names truncations

Increase the size of led_names so it can fit any valid v4l2 device name.

Fixes:
drivers/media/radio/radio-shark2.c:197:17: warning: ‘%s’ directive output may be truncated writing up to 35 bytes into a region of size 32 [-Wformat-truncation=]

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>