drm/i915/display: rename intel_display_driver_suspend/resume functions

Follow the usual naming conventions. Switch to i915 arguments and naming
while at it.

Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/cdd4228337678609967ed176dcfc9690de5d490b.1681465222.git.jani.nikula@intel.com