drm/exynos: constify exynos_drm_crtc_ops structures

Declare exynos_drm_crtc_ops structures as const as they are only passed
as an argument to the function exynos_drm_crtc_create. This argument is
of type const struct exynos_drm_crtc_ops *, so exynos_drm_crtc_ops
structures having this property can be declared const.
Done using Coccinelle:

@r disable optional_qualifier@
identifier i;
position p;
@@
static struct exynos_drm_crtc_ops i@p={...};

@ok@
position p;
identifier r.i;
@@
exynos_drm_crtc_create(...,&i@p,...)

@bad@
position p!={r.p,ok.p};
identifier r.i;
@@
i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
+const
struct exynos_drm_crtc_ops i;

File size before:
   text	   data	    bss	    dec	    hex	filename
   5008	    280	      0	   5288	   14a8	exynos/exynos5433_drm_decon.o

File size after:
   text	   data	    bss	    dec	    hex	filename
   5120	    176	      0	   5296	   14b0 exynos/exynos5433_drm_decon.o
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1483984493-25284-1-git-send-email-bhumirks@gmail.com

drivers/gpu/drm/exynos/exynos5433_drm_decon.c

@@ -470,7 +470,7 @@ static void decon_clear_channels(struct exynos_drm_crtc *crtc)
 		clk_disable_unprepare(ctx->clks[i]);
 }
 
-static struct exynos_drm_crtc_ops decon_crtc_ops = {
+static const struct exynos_drm_crtc_ops decon_crtc_ops = {
 	.enable			= decon_enable,
 	.disable		= decon_disable,
 	.enable_vblank		= decon_enable_vblank,