agp/via: Update to DEFINE_SIMPLE_DEV_PM_OPS()

As of 1a3c7bb0 ("PM: core: Add new *_PM_OPS macros, deprecate old
ones"), SIMPLE_DEV_PM_OPS() is deprecated in favor of
DEFINE_SIMPLE_DEV_PM_OPS(), which has the advantage that the PM callbacks
don't need to be wrapped with #ifdef CONFIG_PM or tagged with
__maybe_unused.

Convert to DEFINE_SIMPLE_DEV_PM_OPS().  No functional change intended.

Link: https://lore.kernel.org/r/20221025203852.681822-9-helgaas@kernel.org


Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>