i965/miptree: Use intel_miptree_copy for maps

i965/miptree: Use intel_miptree_copy for maps

What we're really doing is copying a texture not blitting it in the sense
of glBlitFramebuffers.  Also, the intel_miptree_copy function is capable of
properly handling compressed textures which intel_miptree_blit is not.

Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97473
Cc: "13.0" <mesa-stable@lists.freedesktop.org>