drm/vmwgfx: Constify function pointer structs

Moves a bunch of junk to .rodata from .data.

 drivers/gpu/drm/vmwgfx/vmwgfx.ko:
-.text                       132244
+.text                       132240
-.rodata                      18296
+.rodata                      18680
-.data                         5096
+.data                         4712

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450178476-26284-28-git-send-email-boris.brezillon@free-electrons.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 9394c35..162f188 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -470,7 +470,7 @@
 }
 
 
-static struct drm_framebuffer_funcs vmw_framebuffer_surface_funcs = {
+static const struct drm_framebuffer_funcs vmw_framebuffer_surface_funcs = {
 	.destroy = vmw_framebuffer_surface_destroy,
 	.dirty = vmw_framebuffer_surface_dirty,
 };
@@ -647,7 +647,7 @@
 	return ret;
 }
 
-static struct drm_framebuffer_funcs vmw_framebuffer_dmabuf_funcs = {
+static const struct drm_framebuffer_funcs vmw_framebuffer_dmabuf_funcs = {
 	.destroy = vmw_framebuffer_dmabuf_destroy,
 	.dirty = vmw_framebuffer_dmabuf_dirty,
 };