i965/miptree_map_blit: Don't do the initial copy if INVALIDATE_RANGE is set

i965/miptree_map_blit: Don't do the initial copy if INVALIDATE_RANGE is set

Before we were always coping from the buffer being mapped into the
temporary buffer.  However, if INVALIDATE_RANGE is set, then we know that
the data is going to be junk after we unmap so there's no point in doing
the blit.  This is important because doing the blit will cause a stall 3
lines later when we map the buffer.

Signed-off-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>