media: allegro: implement S_FMT for CAPTURE

In order to support different codecs, the driver must support changing
the format on CAPTURE. Therefore, the driver needs to handle S_FMT on
CAPTURE.

As the driver will have a different number of formats for OUTPUT and
CAPTURE, split the check for the format index in ENUM_FMT into CAPTURE
and OUTPUT.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>