v3d: Minor fixes on sand8 blit based on sand30 modifications

v3d: Minor fixes on sand8 blit based on sand30 modifications

* load_uniform for sand8_stride is uint32 instead of int32 and its range
  is 4 instead of 1 as it is counted in bytes.
* Now we save and restore constant buffer 1 properly for the ubo used
  in the blit. We need to take into account that in V3D the first UBO
  with index 0 is stored on constant buffer 1, because gallium uses
  internally contant buffer 0 (See for reference commit c8212731e7d67a7)
* Removed not needed return.
* Added shader information about uniforms, ubos, inputs and outputs.
* Fixed typos in the comments.

Fixes: 95c4f0f91098 "v3d: Enables DRM_FORMAT_MOD_BROADCOM_SAND128 support"
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19639>