Use the csc library functions to configure the CSC block in VPE.

Some changes are required in try_fmt to handle the pix->colorspace parameter
more correctly. Previously, we copied the source queue colorspace to the
destination queue colorspace as we didn't support RGB formats. Now, we configure
pix->colorspace based on the color format set(and the height of the image if
it's a YUV format).

Add basic RGB color formats to the list of supported vpe formats.

If the destination format is RGB colorspace, we also need to use the RGB output
port instead of the Luma and Chroma output ports. This requires configuring the
output data descriptors differently.

Also, make the default colorspace V4L2_COLORSPACE_SMPTE170M as that resembles
the Standard Definition colorspace more closely.
Signed-off-by: Archit Taneja <archit@ti.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>