[media] media Kconfig: improve the spi integration

The SPI driver looked a bit lonely in the config menu, and it didn't
support the autoselect. Shift things around a bit so it looks more logical.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>