Fix cheese_camera_device_update_format_table loop

Some devices report a very small min_width / height down to reporting
0x0 as minimum resolution, which causes an infinite loop in
cheese_camera_device_update_format_table().

This patch limits the minimum resultion to 160x120, both to fix the
infinite loop issue, and to remove ridiculous resolutions such as 2x2,
5x3, 11x7, 22x15 etc. which are seen in the resolution drop down on some
devices.

For more details on the infinite loop issue, see:
https://bugzilla.redhat.com/show_bug.cgi?id=850505



Signed-off-by: Hans de Goede <hdegoede@redhat.com>