media: ti-vpe: cal: remove cal_camerarx->fmtinfo

struct cal_camerarx has fmtinfo field which is used to point to the
current active input format. The only place where the field is used is
cal_camerarx_get_ext_link_freq().

With multiple streams the whole concept of single input format is not
valid anymore, so lets remove the field by looking up the format in
cal_camerarx_get_ext_link_freq(), making it easier to handle the
multistream-case in the following patches.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>