[media] media: i2c: tvp514x: Reported mbus format should be MEDIA_BUS_FMT_UYVY8_2X8

The advertised V4L2 pixel format and Media Bus code don't match.
The current media bud code advertised is MEDIA_BUS_FMT_YUYV8_2X8
which does not reflect what the encoder actually outputs.
This encoder generate MEDIA_BUS_FMT_UYVY8_2X8 so advertise as such.

Signed-off-by: Benoit Parrot <bparrot@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>