qv4l2 crashes if output device implements VIDIOC_ENUM_FRAMESIZES

[Martin Tůma <tumic@xxxxxxxxxx>]

Hi,
If a driver implements VIDIOC_ENUM_FRAMESIZES for a output device, qv4l2 
crashes in general-tab.cpp:2169 due to m_frameSize being 0. As all other 
usages of m_frameSize in the GeneralTab::updateFrameSize() function are 
guarded by "NULL checks" an obvious fix would be to guard the "addItem 
while cycle" as well. But maybe a better solution would be to add the 
frame size combobox to output devices as well. Or are the output devices 
not supposed to have frame sizes enumeration?

M.