drm/gma500: Don't store crtc_funcs in psb_ops

The drm_crtc_funcs are all generic and no chip specific functions are
necessary. We can therefore directly put gma_crtc_funcs into the
drm_crtc.

Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220317092555.17882-3-patrik.r.jakobsson@gmail.com