drm/imx/dcss: Use GEM DMA fbdev emulation

Use the fbdev emulation that is optimized for DMA helpers. Avoids
possible shadow buffering and makes the code simpler.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230313155138.20584-8-tzimmermann@suse.de

drivers/gpu/drm/imx/dcss/dcss-kms.c

@@ -7,7 +7,7 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge_connector.h>
 #include <drm/drm_drv.h>
-#include <drm/drm_fbdev_generic.h>
+#include <drm/drm_fbdev_dma.h>
 #include <drm/drm_gem_dma_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_of.h>
@@ -145,7 +145,7 @@ struct dcss_kms_dev *dcss_kms_attach(struct dcss_dev *dcss)
 	if (ret)
 		goto cleanup_crtc;
 
-	drm_fbdev_generic_setup(drm, 32);
+	drm_fbdev_dma_setup(drm, 32);
 
 	return kms;