clui: fix Clipper() function
clui: fix Clipper() function

We're using the wrong control to calculate the clipped area, it should
be the clipped control not its clipped parent.

Signed-off-by: Leandro Dorileo <27489cbbb360dd9a8af745ba3f6e7d2c506ebdd9@intel.com>

VladimirMarkelov/clui