It is not immediately clear why DDS compressed (DXT/S3TC) textures need
to be power of two in size (since nothing in DXT/S3TC intrinsically
requires that). It is only needed due to the "flip the texture upside
down" dance that we do for DDS at load time.
While at it, when logging DXT related messages, tell which texture
was it for, and dimensions. This changes logs like:
```
Unable to load non-power-of-two DXT image resolution, falling back to uncompressed.
Unable to load non-power-of-two DXT image resolution, falling back to uncompressed.
Unable to find a suitable DXT compression, falling back to uncompressed.
```
Into:
```
Unable to load non-power-of-two DXT image resolution, falling back to uncompressed (281splash-dxt1-mips.dds, 890x501).
Unable to load non-power-of-two DXT image resolution, falling back to uncompressed (281splash-dxt5-mips.dds, 890x501).
Unable to find a suitable DXT compression, falling back to uncompressed (281splash-rgba8-mips.dds, 890x501).
```
Pull Request: https://projects.blender.org/blender/blender/pulls/120210
b3ea1e75dc