drm/xe: use pdev_to_xe_device() instead of pci_get_drvdata() directly

We have a helper for converting pci device to xe device, use it.

Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1b87c2e56200e001ce3a5d2f4a93eb26b294df32.1723458544.git.jani.nikula@intel.com


Signed-off-by: Jani Nikula <jani.nikula@intel.com>