drm/mediatek: Introduce GEM object functions

static struct drm_driver mtk_drm_driver = {

	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,

	.gem_free_object_unlocked = mtk_drm_gem_free_object,

	.gem_vm_ops = &drm_gem_cma_vm_ops,

	.dumb_create = mtk_drm_gem_dumb_create,

	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,

	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,

	.gem_prime_import = mtk_drm_gem_prime_import,

	.gem_prime_get_sg_table = mtk_gem_prime_get_sg_table,

	.gem_prime_import_sg_table = mtk_gem_prime_import_sg_table,

	.gem_prime_mmap = mtk_drm_gem_mmap_buf,

	.gem_prime_vmap = mtk_drm_gem_prime_vmap,

	.gem_prime_vunmap = mtk_drm_gem_prime_vunmap,

	.fops = &mtk_drm_fops,

	.name = DRIVER_NAME,

#include <drm/drm.h>

#include <drm/drm_device.h>

#include <drm/drm_gem.h>

#include <drm/drm_gem_cma_helper.h>

#include <drm/drm_prime.h>

#include "mtk_drm_drv.h"

#include "mtk_drm_gem.h"

static const struct drm_gem_object_funcs mtk_drm_gem_object_funcs = {

	.free = mtk_drm_gem_free_object,

	.get_sg_table = mtk_gem_prime_get_sg_table,

	.vmap = mtk_drm_gem_prime_vmap,

	.vunmap = mtk_drm_gem_prime_vunmap,

	.vm_ops = &drm_gem_cma_vm_ops,

};

static struct mtk_drm_gem_obj *mtk_drm_gem_init(struct drm_device *dev,

						unsigned long size)

{

	if (!mtk_gem_obj)

		return ERR_PTR(-ENOMEM);

	mtk_gem_obj->base.funcs = &mtk_drm_gem_object_funcs;

	ret = drm_gem_object_init(dev, &mtk_gem_obj->base, size);

	if (ret < 0) {

		DRM_ERROR("failed to initialize gem object\n");