i965: Drop a bunch of downcasting and upcasting of gl_program pointers.

We have a gl_program and we want a gl_program.  There's no point in
converting to brw_program and back again.  This probably made more
sense in the old days before Tim dropped a layer of subclassing.

Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>
1 file changed