i965: Round copy size to the nearest block in intel_miptree_copy

i965: Round copy size to the nearest block in intel_miptree_copy

The width and height of the copy don't have to be aligned to the block
size if they specify the right or bottom edges of the image.  (See also
the comment and asserts right above).  We need to round them up when we
do the division in order to get it 100% right.

Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Cc: "17.0 17.1" <mesa-stable@lists.freedesktop.org>