Refactor: GPU: Remove unnecessary C wrappers for textures

This is the first step into merging `DRW_gpu_wrapper.hh` into
the GPU module.

This is very similar to #119825.

Pull Request: https://projects.blender.org/blender/blender/pulls/142732

intern/cycles/blender/display_driver.cpp

@@ -261,7 +261,7 @@ class DisplayGPUTexture {
   /* Texture resource allocated by the GPU module.
    *
    * NOTE: Allocated on the render engine's context. */
-  GPUTexture *gpu_texture = nullptr;
+  blender::gpu::Texture *gpu_texture = nullptr;
 
   /* Dimensions of the texture in pixels. */
   int width = 0;