nvc0: stick compute kernel arguments into uniform_bo

nvc0: stick compute kernel arguments into uniform_bo

Having one buffer object for input kernel arguments coming from clover
and an other one for OpenGL user uniforms is unnecessary. Using the
uniform_bo object for both GL/CL uniforms avoids to declare a new BO.

This only affects compute programs but it should not hurt anything
because the states are dirtied and data will get reuploaded.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>