`Ogre::Image` debug assert from `ColorMap::_getColorMap_Billinear()`

[ohlidalp]

Apparently the x < mWidth check fails because both values are 256.

Windows10, Visual Studio 2022, Debug build with OGRE 14.4.1

Stack and locals from ColorMap::_getColorMap_Billinear():

	Name	Value	Type
	mapHeight	256	unsigned int
	mapWidth	256	unsigned int
	x	2994.44165	float
	xIndex	255	unsigned int
	xIndexFloat	255.025681	float
	xRatio	0.0256805420	float
	xRatioInv	0.974319458	float
	z	1624.06433	float
	zIndex	138	unsigned int
	zIndexFloat	138.086823	float
	zRatio	0.0868225098	float
	zRatioInv	0.913177490	float

[paroj]

the assert is right. This is a out of bounds access at the border. It should probably be clamped (std::min)