Remove src_pixels_per_line and pixel_step from bilinear second pass.
Remove src_pixels_per_line and pixel_step from bilinear second pass.

These were both equal to the output width and unnecessary.

awatry/libvpx.opencl,awatry/libvpx.opencl,awatry/libvpx.opencl,awatry/libvpx.opencl