intel: Silence several "warning: unused parameter"

intel: Silence several "warning: unused parameter"

The internalFormat, format, and type parameters were not used by
either try_pbo_upload or try_pbo_zcopy, so remove them.  The width
parameter was also not used by try_pbo_zcopy (because it doesn't
actually copy anything), so remove it too.

Eric Anholt notes:

    The current structure of this code is so hateful I can't bring
    myself to say anything about whether changing the current code is
    good or bad.

    I have a dream that one call would try to make a surface
    (miptree/region) out of the PBO, then we'd see about whether it
    matches up nicely and zero-copy/blit using that.  That would be
    reusable for texsubimage, which is currently awful in this
    respect.

At some point we should revisit this code with pitchforks and torches.