[media] mem2mem_testdev: pick default format with try_fmt
[media] mem2mem_testdev: pick default format with try_fmt

This resolves an issue raised by v4l2-compliance: if the given format does
not exist, then pick a default format.

While there is an exception regarding this for TV capture drivers, this
m2m driver should do the right thing.

Signed-off-by: Hans Verkuil <3a513708f73c27e7d36ebc496aa41dad6a3153ea@cisco.com>
Signed-off-by: Kamil Debski <c76391f0c6ca952c7a383ba141fbed195fa466af@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <0cae1d1e981e84d16b82ca3d17be8a7f826608d3@samsung.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs