common: Correct PBO 2D_ARRAY handling.

common: Correct PBO 2D_ARRAY handling.

Changes PBO uploads and downloads to use a tall (height * depth) 2D texture
for blitting. This fixes the bug where 2D_ARRAY, 3D, and CUBE_MAP_ARRAY
textures are not properly uploaded and downloaded.

Removes the option to use a 2D ARRAY texture for the PBO during upload and
download.  This option didn't work because the miptree couldn't be set up
reliably.

v2: Review from Jason Ekstrand and Neil Roberts:
   -Delete the depth parameter from create_texture_for_pbo
   -Abandon the option to create a 2D ARRAY texture in create_texture_for_pbo

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Cc: "10.4, 10.5" <mesa-stable@lists.freedesktop.org>