r600: fix textureSize queries with tbos

r600: fix textureSize queries with tbos

piglit doesn't care, but I'm quite confident that the size actually bound
as range should be reported and not the base size of the resource (and
some quick piglit test hacking confirms this).
Also, the array in the constant buffer looks overallocated by a factor of 4.
For eg, also decrease the size by another factor of 2 by using the same
constant slot for both buffer size (required for txq for TBOs) and the number
of layers for cube arrays, as these are mutually exclusive. Could of course use
some more logic and only actually do this for the samplers/images/buffers where
it's required rather than for all, but ah well...

Reviewed-by: Dave Airlie <airlied@redhat.com>