drm/gma500: Remove unnecessary suspend/resume wrappers

The psb_runtime_suspend/resume/thaw/freeze/restore functions are all
just 1:1 wrappers around gma_power_suspend/_resume.

Drop these wrappers and use the DEFINE_RUNTIME_DEV_PM_OPS() macro to
define the dev_pm_ops struct.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220909115646.99920-7-hdegoede@redhat.com