media: atmel: atmel-isc: make try_fmt error less verbose

In case the sensor refuses to set the format, avoid printing the error
message that no compatible format was found.
This means that the try_fmt will be less verbose.
The error will be printed only if really a format cannot be found.
Some application try all possible formats in a row (gstreamer e.g.)
which will flood the console with error messages until a working one is found.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>