media: atmel: atmel-sama5d2-isc: fix wrong mask in YUYV format check

While this does not happen in production, this check should be done
versus the mask, as checking with the YCYC value may not include
some bits that may be set.
It is correct and safe to check the whole mask.

Fixes: 123aaf81 ("media: atmel: atmel-sama5d2-isc: fix YUYV format")
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>