drm/xe/configfs: Improve documentation steps

drm/xe/configfs: Improve documentation steps

The steps are roughly:

1. Load the module without binding to the device
2. Configure the desired device
3. Bind the device

Move the binding part to the "Create devices" since it's not exclusive
to the survivability_mode attribute and better document the steps.

Reviewed-by: Riana Tauro <riana.tauro@intel.com>
Link: https://lore.kernel.org/r/20250821-psmi-v5-10-34ab7550d3d8@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>