drm: armada: use vblank hooks in struct drm_crtc_funcs

The vblank hooks in struct drm_driver are deprecated and only meant for
legacy drivers.  For modern drivers with DRIVER_MODESET flag, the hooks
in struct drm_crtc_funcs should be used instead.  As the result,
functions armada_drm_crtc_enable[disable]_irq() can be static, although
they are moved around a bit to save forward declaration.

The armada_crtc pointer array in struct armada_private is still kept in
there, because armada_debugfs.c still have reference to it.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Cc: Russell King <linux@armlinux.org.uk>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1486458995-31018-7-git-send-email-shawnguo@kernel.org

drivers/gpu/drm/armada/armada_crtc.h

@@ -104,8 +104,6 @@ struct armada_crtc {
 
 void armada_drm_crtc_gamma_set(struct drm_crtc *, u16, u16, u16, int);
 void armada_drm_crtc_gamma_get(struct drm_crtc *, u16 *, u16 *, u16 *, int);
-void armada_drm_crtc_disable_irq(struct armada_crtc *, u32);
-void armada_drm_crtc_enable_irq(struct armada_crtc *, u32);
 void armada_drm_crtc_update_regs(struct armada_crtc *, struct armada_regs *);
 
 void armada_drm_crtc_plane_disable(struct armada_crtc *dcrtc,