skip_try_fmt_probes quirk is set, V4L2 object will not probe for
interlace-mode and colorimetry to avoid relying on try_fmt. This quirk
will be used by v4l2src to avoid desastrous startup time with slow
USB webcams.

When this quirk is enabled, caller will have to iterate over the
negotiated caps as it may contains unsupported formats. If the peer
didn't choose a specific interlace-mode, or colorimetry, the value
chosen by the driver is set into the caps. For this reason, when this
mode is enabled, gst_v4l2_object_set_format() will require writable
caps.

https://bugzilla.gnome.org/show_bug.cgi?id=785156