drm/gma500: Remove a couple of not useful function wrappers

The gma_crtc_set_config() and psb_unlocked_ioctl() functions are 1:1
wrappers for drm_helpers. Drop these wrappers.

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/20220909115646.99920-5-hdegoede@redhat.com