[media] s5k4ecgx: select CRC32 helper

A rare randconfig build failure shows up in this driver when
the CRC32 helper is not there:

drivers/media/built-in.o: In function `s5k4ecgx_s_power':
s5k4ecgx.c:(.text+0x9eb4): undefined reference to `crc32_le'

This adds the 'select' that all other users of this function have.

Fixes: 8b99312b

 ("[media] Add v4l2 subdev driver for S5K4ECGX sensor")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>