vl: add a bicubic interpolation filter(v5)

vl: add a bicubic interpolation filter(v5)

This is a shader based bicubic interpolater which uses cubic
Hermite spline algorithm.

v2: set dst_area and dst_clip during scaling (Christian)
v3: clear the render target before rendering
v4: intialize offsets while initializing shaders
    use a constant buffer to send dst_size to frag shader
    small changes to reduce calculation in shader
v5: send half pixel offset instead of sending dst_size

Signed-off-by: Nayan Deshmukh <nayan26deshmukh@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>