drm/pl111: Use GEM DMA fbdev emulation

Use the fbdev emulation that is optimized for DMA helpers. Avoids
possible shadow buffering and makes the code simpler.
Reported-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/dri-devel/CACRpkdawSQsNqKJkSSoSw3HmMHyNXFUywxkdszpTC-a_uZA+tQ@mail.gmail.com/Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230313155138.20584-26-tzimmermann@suse.de

drivers/gpu/drm/pl111/pl111_drv.c

@@ -48,7 +48,7 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_drv.h>
-#include <drm/drm_fbdev_generic.h>
+#include <drm/drm_fbdev_dma.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_gem_dma_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
@@ -308,7 +308,7 @@ static int pl111_amba_probe(struct amba_device *amba_dev,
 	if (ret < 0)
 		goto dev_put;
 
-	drm_fbdev_generic_setup(drm, priv->variant->fb_bpp);
+	drm_fbdev_dma_setup(drm, priv->variant->fb_bpp);
 
 	return 0;